Dr Layne Norton: The Science of Eating for Health, Fat Loss & Lean Muscle | Huberman Lab Podcast #97

ANDREW HUBERMAN: Welcome to the Huberman Lab

podcast

, where we discuss

science

and

science

-based tools for everyday life. I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford Medical School. Today my guest is Dr. Layne Norton. Dr. Norton is one of the leading experts in protein metabolism, fat

loss

and nutrition. She earned degrees in biochemistry and nutritional sciences and is considered one of the world's experts in understanding how we extract energy from our food and how exercise and what we eat combine to impact things like body composition and overall

health

. Today, we discuss a huge number of topics under the umbrella of nutrition and fitness, including, for example, what is energy balance?

That is, how do we actually extract energy from our food? We also discussed the somewhat controversial topic of artificial sweeteners, whether or not they are safe and whether or not they are an effective weight

loss

tool, particularly for people suffering from obesity and different types of diabetes. We also talk about gut

health

, meaning the gut microbiome, and how it is affected by food and how it can actually affect the metabolism of the foods we eat. We also look at fasting, or so-called intermittent fasting or time-restricted

eating

, what it does and what it doesn't do in terms of its effectiveness for weight loss and perhaps even health and longevity.

We also talk about protein and define very clearly how much protein each and every one of us needs, based on our daily activities and life demands. We look at the different types of diets you've probably heard of, including ketogenic diets, vegan diets, vegetarian diets, and pure carnivore diets, as well as more typical omnivore diets, and how to make sure you're getting all the essential nutrients. amino acids that are essential for maintaining a healthy weight, weight loss or targeted

muscle

gain. We also talk about supplements, particularly those for which there is an immense amount of science pointing to their safety and effectiveness for fitness and overall body composition.

What I'm sure will become clear to you, as you listen to Layne talk about each and every one of these topics, is that he has an incredible ability to understand the mechanistic science but also the real-world applications of the various discoveries that are being made . carried out in particular articles and, in particular, in randomized controlled trials. It is then when a certain scientific hypothesis has been raised. It's extremely good at understanding why the topic was brought up, but also at evaluating whether or not it works in the real world, which is what I think most people are worried about.

I think this is one of the things that really sets him apart from the other voices in the nutritional landscape. I assure you that by the end of today's discussion, you will have a much clearer understanding of what science says about nutrition, fitness, and how different diets and fitness programs work together to achieve the results you want. Before we begin, I would like to emphasize that this

podcast

is independent of my teaching and research duties at Stanford. However, it is part of my desire and effort to bring zero-cost information about science and science-related tools to the general public.

In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is LMNT. LMNT is an electrolyte drink with everything you need and nothing you don't. This means that it contains sodium, potassium and magnesium, the so-called electrolytes, but no sugar. As you may have heard me comment before in this podcast, each cell in our body, and in particular the cells in our brain, the so-called neurons or nerve cells, depend critically on the presence of electrolytes: sodium, magnesium and potassium. -- for it to work correctly. I myself am a big believer in consuming electrolytes whenever I've been sw

eating

a lot, so it could be after exercise or after going to the sauna.

So by drinking electrolytes in the form of LMNT electrolyte blend, I can replenish those electrolytes and maintain mental clarity and energy throughout the day. LMNT contains a scientific electrolyte ratio of 1,000 milligrams of sodium, 200 milligrams of potassium, and 60 milligrams of magnesium. If you want to try an LMNT, you can go to drinklmnt-- spelled L-M-N-T-- .com/

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to get a free sample pack with your purchase. Again, visit www.drinkL-M-N-T.com/

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for the free sample pack. Today's episode is also brought to us by ROKA. ROKA manufactures the highest quality eyeglasses and sunglasses. The company was founded by two all-American swimmers from Stanford.

And everything about ROKA eyeglasses and sunglasses was designed with performance in mind. I've spent my entire life working on biology, the visual system, and I can tell you that your visual system has to face an enormous number of challenges in order for you to see clearly, for example, when you move from a sunny location. area to a shadowed area and vice versa, whether you are looking at something up close or often in the distance. ROKA understands the biology of the visual system and has designed its glasses and sunglasses accordingly so that you always see with perfect clarity.

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Again, that's roka-- R-O-K-A-- .com and enter the code Huberman at checkout. InsideTracker also brings us today's episode. InsideTracker is a personalized nutrition program that analyzes data from your blood and DNA to help you better understand your body and achieve your health goals. Now, I have long believed in the need for regular blood testing for the simple reason that many of the factors that affect your immediate and long-term health can only be analyzed with a quality blood test. However, one of the main problems with many blood and DNA tests is that you get information about hormone levels, lipid levels, and levels of metabolic factors, but you don't know what to do with that information. .

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And I just have to mention that the library of those supplements is constantly expanding. Again, that's livemomentous.com/huberman. And now, my conversation with Dr. Layne Norton. Layne, Dr. Norton, thank you very much for being here. This will be a long time coming. And I have to say that I am very excited because I have seen you in the social media sphere. I also listened to several of his other podcasts. And as a fellow PhD scientist, I feel a great kinship with you. I know you have enormous experience in fitness and nutrition, in several areas. We also received many questions from our audience.

And I'm looking forward to talking to you today. LAYNE NORTON: Yeah, I'm excited too. I mean, like you said, it's something we've been talking about for a long time. So I was glad we could make it happen. ANDREW HUBERMAN: Yes, indeed. And I think part of the public has asked for a debate or a battle. And I can tell you right now that that's not going to happen. Actually, one of the things that brought Layne and I together, in online conversations and then through text messages, etc., was the fact that I love being corrected, and that's what happened.

I did a post on artificial sweeteners, which we'll talk about a little later in the episode, and Layne pointed out some areas of the study that I had overlooked or perhaps even misunderstood. And I checked my reviews and I think it's wonderful. And since then other studies have emerged. So hopefully our conversation will serve as a message about how science and practical science can be perceived and that it doesn't always have to be a battle. But hey, if we get into it, we get into it. It won't be physical because we know you would win. In any case, I would like to start with something that is quite basic but can be quite complex, and that is the question of energy balance and energy utilization.

I think most people have heard of calories. I guess most people don't really know what that is in terms of how it works, what it represents. So maybe you could explain to people what happens when we eat food, of any kind, and how it is actually converted into energy, as a way to frame the discussion about weight loss, weight maintenance, weight gain, and body composition. . LAYNE NORTON: That's a great question. And like you said, this is one of those things where people use the term calories in, calories out and say, well, that's too simplistic. I say, if you look at what actually constitutes calories in and calories out, it's actually very complicated.

So let's address what you mentioned first. What is the calorie? Because I think a lot of people don't fully understand this. So, a calorie simply refers to a unit of energy, specifically heat. And what does that have to do with food? What does that have to do with what we digest and eat? Really, what you're talking about is the potential chemical energy in the bonds of macronutrients in foods. And by digesting, assimilating and metabolizing these nutrients, we can create energy and the product of that, mainly, is ATP, adenosine triphosphate, which is the body's energy currency. So to understand ATP, just try to think about... if you're trying to drive these various reactions in your body, and we're talking about tens of thousands of enzymes that require ATP, it doesn't make sense that you'd have to create a bunch of microexplosions.

You want something that can transfer high-energy phosphates to drive these reactions, essentially giving up its energy to drive something that might otherwise be unfavorable. So a lot of metabolism just creates ATP, and the bottom line of that (I'm going to work backwards) is what's called oxidative respiration. That happens in the mitochondria. Everyone has heard of mitochondria, the powerhouse of the cell. And that's done by essentially creating a hydrogen ion gradient across the mitochondria, which drives ATP production by converting free phosphate plus ATP into ADP. Now, the way that the hydrogen ion gradient is created is by creating hydrogen ions that can be donated through the Krebs cycle.

Now the Krebs cycle is linked to glycolysis. So if we talk about carbohydrate metabolism, basically carbohydrates other than fructose are converted into glucose, which can go into glycolysis, and some ATP can be produced through glycolysis. And then it's reduced to pyruvate, then acetyl-CoA, which goes to the Krebs cycle, makes a lot more ATP from there. If you're talking about proteins, proteins are a little different because proteins are converted into amino acids, which can be used for

muscle

protein synthesis or protein synthesis in other tissues. But it can also be converted through gluconeogenesis into glucose. And there are also some ketogenic amino acids.

And then you can have a few different ways to get to the Krebs cycle. Either through acetyl-CoA or through glucose going through glycolysis to pyruvate. Then there are fatty acids, which are able to create energy through what is called beta oxidation, where, essentially, you take these fatty acids and cut two carbons at a time to produce acetyl-CoA which, again, can go into in the Krebs cycle, produce those hydrogen ions that can then drive ATP production. So that's kind of like on a cellular level how these things work. But taking a step back and putting it back out, what does that have to do with weight loss or weight gain?

Well, when you think about the balance between the energy coming in and the energy going out. It sounds very simple. But let's look at what actually constitutes the energy going in and the energy going out. First of all, you must realize that the energy within the equation is moreHarder to track than people think. For example, food labels, which we like to think come from above, can be up to 20% wrong. ANDREW HUBERMAN: Really? LAYNE NORTON: Oh, yeah. ANDREW HUBERMAN: So 100 calories... something listed as 100 calories per serving, could... what's actually there could be 80 or 120. LAYNE NORTON: Right. Exactly.

So that's one aspect of this. The second aspect is what is called energy, but there is also metabolizable energy. So if you have foods with a lot of insoluble fiber, usually the insoluble fiber is not really digestible, so you could have "plenty of carbs", but if you can't extract energy from them... - and usually, this is This is because the insoluble fiber of plant material, carbohydrates and even some proteins are bound to the structure of the plant, making it inaccessible to digestive enzymes. And this is what adds bulk to the stool and all that. But again, it reduces the metabolizable energy there.

And there is some evidence that, depending on people's individual gut microbiome, some people may be better at extracting energy from fiber compared to others. So starting from there, okay, there's quite a bit of play in the energy within things. Now, one of the things people will say is, well, look, that's why you shouldn't worry about tracking calories, because food tiers can be 20% off. And what I will say is, that's okay. I understand where you're coming from. But normally, if it is off, it will be off constantly. And if you're consistent with how you track it, you'll eventually be able to know what you're absorbing.

And that's like saying, well, don't worry about tracking if you're... Like Use financial examples. We know that to save money you have to earn more money than you spend. Well, you can't know exactly how much money you're making at a time because there's inflation and then there's... if you have investments, it might be different interest rates and all that. It's like, okay, if you have a budget, you have a reasonable idea of ​​what it's going to be. And you make certain assumptions, but you can guess relatively. ANDREW HUBERMAN: Yes. That's a good example. LAYNE NORTON: Right.

Now, let's look at energy out of the equation, which is actually much more complicated. And so your energy spent is in a few different buckets. The first and most important is the resting metabolic rate. Then your RMR. And that, for most people, represents between 50% and 70% of their total daily energy expenditure. Now, people use the term metabolic rate and energy expenditure interchangeably, but they are not the same. So, your total daily energy expenditure is the sum of all the energy you expend in a day. ANDREW HUBERMAN: Going up the stairs, exercise if you do... LAYNE NORTON: Restless.

ANDREW HUBERMAN: Yes. Plus your resting metabolic rate. LAYNE NORTON: Right. So resting metabolic rate is a big part of that, but it's not the only thing. Typically, that's between 50% and 70%. And sedentary people will be at the higher end of that number. So it will be a higher proportion, while people who are more active will be a little lower, not because their metabolic rate is lower, but because they spend a higher percentage of their calories on physical activity. Then we have something called the thermic effect of food, which represents a relatively small percentage of our total daily energy expenditure.

It's around 5% to 10%. And it's very difficult to measure, and typically what researchers do when they look at this stuff is they just make assumptions about it. They use a constant. But that represents between 5% and 10% of your daily energy expenditure. And that refers to the amount of energy it takes to extract energy from food. So think of your body as a car. Not only do you have gas in the tank and it starts spontaneously. You have to have a battery to put energy and be able to get it from the gasoline you have in your car. Just like with food, you can't just eat food and then it just shows up in your cells and you start doing things.

It has to be systematically broken down and put into forms that can actually produce energy. And then you have to put some energy into it. And a lot of times, people will say something like, well, not all calories are created equal. That is not true, because the calorie is just a unit of measurement. That would be like saying that not all seconds on a clock are equal. Yes they are. All calorie sources can have differential effects on energy expenditure and appetite. So if we look at something like fat, for example, the TEF of fat is about 0% to 3%.

That is, if you eat 100 calories of fat, your net intake will be 97 to 100. ANDREW HUBERMAN: So the process of breaking down that fat, essentially, subtracts some of the calories because you used them to create energy.-- LAYNE NORTON: Correct. ANDREW HUBERMAN: --breaking those chemical bonds to create ATP. LAYNE NORTON: Right. Correct. For example, there are some enzymes that require ATP to execute these processes. Now, fat is actually the easiest thing to convert into energy. Then there are carbohydrates, which have a TEF of between 5% and 10%. So you eat 100 calories of carbohydrates. And obviously, fiber content makes a big difference in this.

But if you eat 100 calories, you will get 92 95. Protein is about 20% to 30% TEF. So if you eat calories from protein, you're only going to get about 70 to 80. Now, you're still net: People say, well, you can't eat too much protein. Well, people will ask, well, can protein be stored as fat? The carbon is unlikely to come from proteins; It will end up in adipose tissue. But if you're eating a lot of protein, usually as part of a lot of calories, it has to be oxidized and can't provide a calorie cushion for other things to be stored in fat.

But protein itself provides a net positive benefit in calories, but less than carbohydrates or fats. And it tends to be more satiating. Again, when people talk about whether all calories are equal, yes, but all calorie sources can have different effects on energy expenditure and appetite. So that's the TEF reservoir and the BMR reservoir. Then we move on to physical activity. And physical activity essentially consists of two parts. There's exercise, which is purposeful movement, like going for a walk or doing a workout. I mean, whatever. Any purposeful activity. And then there's what's called NEAT, which is non-exercise activity thermogenesis, which I think is really cool.

ANDREW HUBERMAN: It's fascinating. LAYNE NORTON: Yes. It is. I was with someone last night and I noticed that he was moving his feet and fingers. And I said, have you always been pretty thin? And they were like, yeah, I never had a problem staying thin. And when you look at the obesity-resistant phenotype, people think they have a high BMR or they exercise a lot, and actually, it looks just as good. They tend to... if they overeat, they just spontaneously increase their physical activity. Now, people get confused NEAT. I've heard people say, well, I'm going to go for a walk to get my NEAT up.

That's not good. NEAT is not something you can consciously modify. What you are doing there, if it has a purpose, is exercise. So, for example, when I speak, if I wave my hands, if I tap my feet, if I'm... whatever. It's very nice. But trying to get it... I'm just going to tap my foot more, well, now if I have to do this consciously, then my approach... I mean, you know how the brain works. It's very difficult to do... you don't really do two things at once. ANDREW HUBERMAN: Right. LAYNE NORTON: You switch quickly between tasks, right?

ANDREW HUBERMAN: Absolutely. Can I quickly ask if the person you were referring to was our friend Ben Bruno? LAYNE NORTON: No, no. But he is also restless. ANDREW HUBERMAN: Yes. Amazing online fitness channel. He is a strangely strong individual. LAYNE NORTON: Yes. ANDREW HUBERMAN: Yes. And I don't remember if, Ben, you're restless or not. But anyway, I'll have to go check it out and we'll gauge your concern. As for non-exercise induced NEAT thermogenesis, from what I understand from old articles on this, I guess they date back to the mid 90's, the calorie burn with NEAT is actually quite significant.

We're not talking about 100 or 200 calories per day. We're talking, in some cases, hundreds of thousands (excuse me, hundreds to maybe even close to 1000 calories per day). Could you give more details on that? LAYNE NORTON: Yeah. So there was actually a really classic study, I think, from... I want to say it's from Levine in 1995. It was a metabolic ward study. And hopefully, I won't trash the studio because I'm trying to get it out of my brain. ANDREW HUBERMAN: I don't expect you to have that in your head. Although, I must say, it has a pretty extensive PubMed ID, grab the bag there.

So... LAYNE NORTON: I try to bring the receipts. I try to bring receipts. ANDREW HUBERMAN: We'll put a link to this study in the titles of the show notes. So that people can read it if they like it, yes. LAYNE NORTON: I think they made people overeat. And I think it was like 1000 calories a day and I think for six weeks. And I mean, this is the metabolic room. So this is very controlled. It is as tight as possible. And the interesting thing is, of course, on average, people gained weight and gained fat mass. But some people gained more than expected, and there was one person in particular who only gained a little more than 1/2 kilo.

They should have gained like... I think it was between 3 and 4 kilos. It planned. And what they found is that this individual just spontaneously increased his physical activity. He didn't do it on purpose, it just happened. And I mean, anecdotally, I've seen people who, again, are very skinny, even eat, sit down, and start sweating. And be very restless. There was a natural bodybuilder at that time named Jim Cordova. And this guy was very skinny all the time and he had exactly that phenotype. He was walking up a flight of stairs and suddenly he was sweating. Sit down and eat, he is sweating.

He's just... ANDREW HUBERMAN: He's an oven. LAYNE NORTON: I'm just wasting energy. And what's very interesting about NEAT is that it seems to be the most modifiable. I mean, exercise is very modifiable because you can be intentional with it. But from BMR, TEF and NEAT, NEAT seems to be much more modifiable. So even with a 10% body weight reduction, they saw a decrease in NEAT of almost 500 calories per day for a 10% reduction in body weight. Now, there is also a decrease in BMR when you lose weight, firstly, because you now have a smaller body and therefore less energy is needed to block them.

But there is also what is called metabolic adaptation, which is a greater reduction in BMR than expected due to loss of body mass. And that's usually around 15% on average. But it seems to be: new evidence is emerging about the metabolic adaptation of TMB. And it seems to be a little bit... in the transition phases. So if you start a diet within the first few weeks you will have a reduction in BMR which then from then on any further reduction is mainly due to the amount of body mass you lose. And then if, for example, you end a diet and move your calories to maintenance, within a few weeks, BMR starts to increase.

There is still a small reduction, but I used to be someone who thought that BMR, metabolic adaptation, was a big reason why people stopped losing weight or plateaued. And now I think it has a lot more to do with NEAT. ANDREW HUBERMAN: Interesting. And you said it can't be conscious because that will distract us from other activities. I don't know if you've had the opportunity to see this study. And I will send it to you. Maybe it would be fun to create a sort of online zine club about this sometime soon. But there's a study that came out recently from the University of Houston where people do, now, this is a long period of time.

Four hours a day of basically a soleus curl, which is basically a heel raise. A slogan sitting with one foot without weight. And then they looked at a bunch of things about glucose metabolism, glucose disposal, and insulin levels. And they didn't conclude that people burned a ton of calories, but they did conclude that blood sugar regulation was greatly improved. And I think there was a lot of excitement about this on some level, but based on everything you're telling me, this fits perfectly with what's known about what's ordained. So this fell somewhere in between... in the middle, excuse me, a kind of deliberate exercise and spontaneous movement.

I guess they've tried to make that spontaneous movement a little more conscious. LAYNE NORTON: Well, what I will tell people is that if you're worried about NEAT, there's one thing you can do, like these watches, for example, where people say, oh, well, they told me I burned that many calories. They are not accurate for energy expenditure. I mean, it's like there was a meta-analysis in 2018, I mean, between 28% and 93% ofoverestimation of the energy expenditure of these watches. ANDREW HUBERMAN: Fitness track. So for those of you listening, we won't name the brand. But fitness trackers... are wrist-worn fitness trackers.

LAYNE NORTON: And this is widespread. ANDREW HUBERMAN: Okay. LAYNE NORTON: Depending on the brand, it could be more or less, but everyone overestimated how many calories you burn with exercise. So this is actually a great example where people say, well, calories burned and calories burned doesn't work for me, because like in a calorie deficit, I didn't lose weight. When I talk to them, they usually go to an online calculator. It's a few things. They went to an online calculator, entered their information, spit out some calories to eat, ate that, and didn't lose any weight. And it's like, well, what do you think is more likely?

That you're defying the laws of conservation of energy or maybe you didn't get the right number for you? ANDREW HUBERMAN: The measurement tool was off. LAYNE NORTON: Yes. The next thing is that a lot of people weigh in very sporadically. And I tell people if they're going to make weight loss an intentional goal, and again, this can be different for different people, but typically, I tell people to weigh themselves, first thing in the morning or after. You go to the bathroom, you do it every day and you take the average for the week. And then compare it to next week's average.

ANDREW HUBERMAN: Can I ask a... I'm sorry to interrupt, but a quick question about that when you say, go to the bathroom so as not to go into too much detail here unnecessarily, but are you talking about urinating and emptying your bowels? Ideally, because you ate a lot the night before. LAYNE NORTON: Yes. ANDREW HUBERMAN: Yes. I understand. LAYNE NORTON: Yeah. ANDREW HUBERMAN: So wake up, use the bathroom in whatever way you're ready, and then get on the scale, take that measurement, average that over the course of the week, and then maybe every Monday. , take that value and see how it progresses.

LAYNE NORTON: Very good. And the reason I recommend doing it is that if you only weigh yourself sporadically, as someone who weighs themselves fairly regularly, I mean, my weight will fluctuate between 5 and 6 pounds and apparently not change much. And that's just... those short-term changes are fluid. I've had it before, where week after week, my average didn't change. But between the lowest weigh-in from the previous week and the highest weigh-in, it could have been like 8 pounds, right? So if you're someone who just randomly weighs and eats at a calorie deficit, and you just weigh in one day and for some reason you have more fluid, then, oh, see, this doesn't work when actually your average could be going down.

That is one of the reasons and in fact, believe it or not, weight fluctuations are identified as one of the main reasons why people are discouraged from losing weight. Stop buying when they have an upward fluctuation. That's one of the reasons... ANDREW HUBERMAN: Great point. LAYNE NORTON: --one of the reasons low-carb diets tend to work very well from the beginning is because people lose a lot of water weight very quickly and gain that acceptance. So they're, oh, this is working. ANDREW HUBERMAN: Yeah. We can come back to that in a moment because I have theories about how that... when people eat fewer carbohydrates, they excrete more water and you'll see... for the first time, you'll see some definition in your Abs, my God, this diet is amazing.

LAYNE NORTON: Yes. ANDREW HUBERMAN: And fluid loss delivers on that promise. I think fluid loss can cause other things. It could literally make people feel lighter, although it may be... it has some negative effects. I have a quick question and I want to... we'll come back to NEAT in a moment. But when you say calorie burning as a result of exercise, I want to ask you about calorie burning during that exercise. So, for example, if someone is on the treadmill and they see, okay, they burn 400 calories. Actually, I think this is a month where a number of notable podcasters like Bert Kreischer, Tom Segura, Joe Rogan and others, I think they call it "sober October," but in addition to avoiding alcohol, they're burning 500 calories. per day during exercise.

LAYNE NORTON: Yes. ANDREW HUBERMAN: They're measuring it. Many people do this. They think... they track the weather... excuse me, they take stock of how many calories they burned. My understanding is that if that particular form of exercise is a muscle-building form of exercise, at some point later, there could be an increase in muscle if you do everything right, you do everything right, and then you'll burn more energy as a consequence of adding that tissue. . That is a long process and we will discuss it. But I've heard of this increase in oxidative metabolism induced after exercise. I'm probably not using the correct language here.

So if I went out, for example, and did some sprints. Run hard for one minute, jog for one minute, run hard for one minute and do it 10 times. Let's say I burn 400 calories during that exercise session. But I understand that in the following hours my basal metabolic rate will have increased. Is that true and is it important enough to worry about? LAYNE NORTON: So answer both questions. Yes, there appears to be a small increase in metabolic rate and no, it does not appear to be enough to make a difference. So when you look, and again, this is where I tell people, I think I have a good perspective on this, because my undergraduate degree was a biochemistry degree.

So I was very interested in the mechanisms. You know what I mean? It was like, oh, if we do this and this, we'll get this. And then I went to graduate school in nutrition, and then my advisor was great because you could do something here and he could tell you how that would affect the vitamin D metabolism here. ANDREW HUBERMAN: Is this Don Lemon? LAYNE NORTON: Yes, Don Lemon. So he always said, yes, but what will be the result, right? So this is one of the things I changed my mind about. It used to be a lot of, well, I think high-intensity interval training is probably better because you get this post-exercise energy burn that you do see in some of these studies.

But in meta-analyses and more closely controlled studies in which they equate high-intensity interval work and moderate or low intensity cardio, that is, equating work, they see no differences in body fat loss. And to me, if I look at it, that's an example of a mechanism, which is fine, we're seeing this little increase in basal metabolic rate, which should lead to more body fat loss. But remember, again, you are capturing a snapshot in time. But we don't see a difference in body fat loss. So what could be happening? And again, I'm just speculating. But one way to explain it could be that there could be an increase and then there could be a decrease that tends to eliminate it, right?

ANDREW HUBERMAN: I see. And I have to imagine some forms of exercise. This would be very individual, but will increase appetite more than others. So for example, if I go for a 45 minute jog, which I do. A 45-60 minute walk or jog once a week, I just aim to do that or ruck or something like that. Put on a weighted vest and walk. After that, I feel very thirsty, I want to hydrate. But I'm not that hungry. And that goes for all cardio for me. But after weight training, 60 to 90 minutes later, I want to eat the refrigerator.

And obviously, calories in and calories out dictate that that's going to play a big role in whether I gain or lose weight, et cetera. So is it safe to say that the specific form of exercise people choose should be taken into account? Calories in, calories out, so how much do you burn during exercise? Also how much that exercise tends to stimulate the appetite. I don't know if people explore this in their rigorous studies. And whether or not that form of exercise actually increases

lean

muscle mass. Now, we've done the exercise and broken it down into several different dimensions, but this is what you guys are so expert at, analyzing how the different components work individually and together.

So if you could expand on that, I'd love to know what you're thinking. LAYNE NORTON: Yeah. This is actually something really fascinating. So the first thing I want to do is go back to talking about, for example, Bert, Tom, and Joe, we're going to consume 500 calories a day on whatever. So those devices don't measure those things effectively either. Like these watches. But the only thing I will say is that if so, for example, if I do two hours of resistance training, typically, this will say that I burned about 1,000 calories. ANDREW HUBERMAN: That's a lot of resistance training.

LAYNE NORTON: Right. ANDREW HUBERMAN: My weight training consists of a 10-minute warm-up and then an hour of work done. LAYNE NORTON: I just... I love training. ANDREW HUBERMAN: Okay. And you can recover from. My recovery quotient is quite low. So I've been training for over 30 years and I found that if I do more than an hour of hard work in the gym, meaning resistance training, maybe 75 minutes, I'm fine, but beyond that, I have to take Two, maybe even three days off before I can train. My nervous system just doesn't tolerate it well. So I limit it to an hour, you know?

LAYNE NORTON: And part of that to remember is that I've done it for a long period of time. So you couldn't just throw someone in and start making them work two hours a day. They won't do well. ANDREW HUBERMAN: I'd like to take a quick break and thank one of our sponsors, Athletic Greens. Athletic Greens, now called AG1, is a probiotic vitamin and mineral drink that covers all your fundamental nutritional needs. I've been taking Athletic Greens since 2012, so I'm delighted that they're sponsoring the podcast. The reason I started taking Athletic Greens, and the reason I still take Athletic Greens, once or usually twice a day, is that it provides me with the probiotics I need for gut health.

Our intestine is very important, it is populated by intestinal microbiota that communicates with the brain, the immune system and basically with all the biological systems of our body to strongly impact our immediate and long-term health. And those probiotics and Athletic Greens are optimal and vital for microbiotic health. Additionally, Athletic Greens contains a number of adaptogens, vitamins and minerals that ensure that all my fundamental or nutritional needs are met. And it tastes very good. If you want to try Athletic Greens, you can go to Athleticgreens.com.huberman and they will give you five free travel packs that will make it very easy to combine Athletic Greens while traveling, in the car, on the plane, etc.

And they will give you a year's supply of vitamin D3, K2. Again, visit Athleticgreens.com/huberman for the five free travel packs and year's supply of vitamin D3 and K2. LAYNE NORTON: But I will say about calorie trackers, so if I'm used to... Well, I usually burn about 1,000 calories based on this, it's not accurate. But if I go tomorrow and do 1,300, it may not be accurate. I don't know what the exact number is, but I can be relatively sure that it is more than the previous session. And in terms of comparison, it might be fine, like on topic.

And then the other thing I was mulling over was that if you're worried about NEAT, tracking your steps can be helpful because people's step counts can spontaneously decrease when they're on a fat-loss diet, and they don't even notice. do. realize. And that, again, is not a complete measure of NEAT, but what some clients have done with our team building trainers is they will say, Okay, you're at 8,000 steps right now. We're not going to add any purposeful cardio. But whatever you need to do to maintain those 8,000 steps, do it. And sometimes they have to add 15, 20, 30 minutes of cardio, because they are spontaneous activities that they are not even aware of.

ANDREW HUBERMAN: That's a really excellent point. I heard the 10,000 steps per day number was, we all heard it. And then I learned that 10,000 was simply thrown out as an arbitrary number. So we thought about eight-hour intermittent fasting, there's a story behind that because I actually talked to Satchin, and it turns out that the graduate student in his lab did that initial study, which by the way, was in mice, his partner limited it to be in the laboratory for about eight hours. So the eight-hour feeding period is actually the consequence of this person's relationship. So... LAYNE NORTON: That's a really important point that people don't realize when... a lot of people try to copy similar studies from scientists.

And I will tell people, listen, the scientific studies are very limited. You have to be very careful how broadly you apply what's in it. As if they were a very big hammer, that's how I see it. They are not a scalpel, they are a big hammer. And I think, a lot of times, in terms of coaching, scientific studies will tell youwhat not to do instead of what to do, right? But going back to your question about exercise and appetite, first of all, I don't know if there's evidence showing differential effects of different forms of exercise on appetite, it's possible, but again, it could also be like a placebo effect. , good?

Because we, like you and I, for example, grew up in an era where muscle magazines said, well, as soon as you finish your workout, you have the most important meal of the day. And when I say placebo effect, I think people have the wrong idea of ​​what the placebo effect is. They think it's just a feeling. The placebo effect can actually change your physiology. People don't realize this. There is research that shows that a placebo or the power of suggestion is basically as powerful as some pharmaceuticals. And one of the great examples that I like to use is... in fact, there was a study that we just covered in our review of the research on creatine where they did four groups... that were not supplemented with creatine, they were told that they were not supplemented with creatine, not supplemented, they were told they were supplemented, supplemented, they were told they were not, supplemented, until they were.

Basically, it only matters what they were told. ANDREW HUBERMAN: Really. LAYNE NORTON: Oh, yeah. ANDREW HUBERMAN: This is incredible. I need to get this study right so we can link it to a colleague of mine at Stanford. She's been on the podcast. I'd love to introduce you guys because I think you guys really riff. First, she was a D1 athlete and then runs a psychology lab at Stanford. This is Alia Crum. And she's... and she grew up in this very athletic, obviously, and very, very intelligent. And his lab focuses on these belief/placebo effects where if you tell people all the horrible things that stress does to you in terms of memory and cognitive functioning and then you give them a memory test, their performance is very below the initial value.

If you tell them that stress sharpens them in the short term and that adrenaline is a powerful molecule that can really fine-tune various memory systems, memory improves. And it is remarkable. And it is consistent. And they've done this for a variety of different things, including food allergies, for example. Incredible results. In any case, I'm really glad you mentioned this. I take creatine monohydrate and have for years. 5 grams a day. Ino... LAYNE NORTON: And it's great. ANDREW HUBERMAN: And it's great. And I think it's great. So is there a compound effect between thinking it's cool and actually thinking it's cool?

LAYNE NORTON: Not in this study. So I think the thing to point out is that people will misunderstand this as creatine doesn't work. And that's not what it says. What it says is that your beliefs about what it does are probably as powerful as what it does. So they actually did a study, and I don't have the quote, but I think in the last 10 years they told people that they were putting them on anabolic steroids. And even if you didn't know it, they made better profits; Even though they weren't actually taking anabolic steroids, they had better gains than people who weren't told they were using anabolic steroids.

ANDREW HUBERMAN: Incredible. LAYNE NORTON: And those are difficult outcomes. Strength,

lean

body mass, that kind of thing. So when people say, well, I wouldn't fall for the placebo effect, it's like you don't have to fall for it. If you believe it's true, the power of faith is very, very powerful. And as a scientist, I sometimes wish I were ignorant so I could subject myself to the placebo effect more often. ANDREW HUBERMAN: Yes, absolutely. LAYNE NORTON: Getting back on topic, that's just one possible explanation for maybe why. And the same thing happens to me, when I finish a workout, like a resistance training session, I think I'm ready to eat.

Now, if you look at the general literature on exercise and appetite, it's not always what you would expect. Consistently, it seems to show that exercise actually has an appetite suppressing effect. That's why people don't tend to at least completely compensate for the amount of movement they perform. And there's some evidence that... you've probably heard people say, well, exercise is a really poor weight loss tool. If you figure out how many calories you need to burn and do it, you'll end up losing less weight than you would predict. ANDREW HUBERMAN: I have a family member who is perfectly happy to eat less, but he doesn't hate exercise, but he does dislike exercise.

And they are a healthy weight. But I always encourage them to exercise more. And this is an ongoing battle in our sibling relationship. LAYNE NORTON: Well, one thing I would say is that if you exercise regardless of what happens to your body weight, you will be healthier. So exercise is one of the only things that will actually improve your health biomarkers without even losing weight. So that... will improve your insulin sensitivity, inflammation, all of that. So, everyone who is looking for a trick to be healthier practices it, right? ANDREW HUBERMAN: Yes. Crucial point. And I think our mutual friend, Dr.

Peter Attia, has gone on record as saying that several times he has said that of all the things one could take: NMN, et cetera, metformin. Regardless of whether one takes them or not, the positive effects on longevity through biomarkers of regular exercise far outweigh all of those things combined. It's not that those things don't necessarily work, we won't go into them in detail now, but exercise is by far the best thing we can do for our health and life expectancy. LAYNE NORTON: Yes. Absolutely. I agree 100%. And when it comes to weight loss, I think people don't understand the point of exercise.

There's also work by Herman Pontzer that basically showed that, well, if you do 100 calories through exercise, you have a 28-calorie reduction in your basal metabolic rate in response to that. It's kind of like this restricted energy expenditure model. But what I would say is, okay, there's still a net result of 72. So it's still okay, and the other thing is that I think the effects of exercise on weight loss are actually more due to what you do. makes the appetite. So if you look at people who lose weight and keep it off for several years, outliers because most people don't keep it off for years, over 70% of them exercise regularly.

Of people who do not maintain weight loss, how to maintain weight loss, less than 30% exercise regularly. Now that's just a correlation. That doesn't necessarily prove causality. But there are some pretty compelling studies showing that exercise increases sensitivity to satiety cues. Basically, you may have the same satiety signals, but you are more sensitive to them when you exercise. And in fact there's a really classic study from the 1950s on Bengali workers where they looked at, basically, four different quadrants of activity. So there were sedentary, slightly active, moderately active and very active. Basically, depending on your choice of job.

And they had no intervention. They just wanted to track and see how many calories they were actually consuming. It was like a J-shaped curve. So, sedentary people actually ate more food than slightly active or moderately active people. But from slightly active to very active, they almost perfectly offset the amount of calories they should be consuming. To me, that means that when you become active, you can regulate your appetite appropriately or much more appropriately than if you are sedentary. ANDREW HUBERMAN: And do you think this has to do with changes in the brain, brain centers that respond to satiety signals from the periphery, and/or do you think it has to do with changes in blood sugar regulation?

What I was taught, and I don't know if this is still considered true, is that blood sugar spikes will trigger the desire to eat more, even though it's the exact opposite of what you need when you have a blood sugar spike. sugar. And there's this kind of... and we'll get into this when we talk about artificial sweeteners. This is the idea in mind. I think I adopted, perhaps, wrongly, that you eat something that is sweeter, that tastes very good, and suddenly you are on the train of wanting to eat more. And you could imagine how exercise, if it increases satiety signals, could work in different ways.

LAYNE NORTON: Yeah. I think it's... I think the effect is probably primarily at the brain level. Effects on blood sugar: The research that does exist is not very convincing on whether blood sugar drives appetite. Now, if you have hypoglycemia, yes, you will be hungry, but it is a different type of hunger than normal, I feel empty and my stomach growls. Those are...they can go together, but usually hypoglycemia is like, I'm hot, I feel like I'm going to pass out. You want to eat something not because your stomach is growling but because you simply need some fuel.

ANDREW HUBERMAN: It's like you're being dragged down. LAYNE NORTON: Oh, yeah. Absolutely. ANDREW HUBERMAN: I was there when I did longer fasts, which I don't do anymore, and I drink a lot of black coffee. There was probably an electrolyte effect there because coffee excretes sodium and other electrolytes. And then I felt like I needed something. All this as if I needed something which is a kind of desperation. I never want to be here again. Hypoglycemia is very uncomfortable. LAYNE NORTON: It's not fun. So, again, when you look at actual randomized controlled trials of implementing some exercise in a fairly controlled environment, you generally see people who, if anything, eat less instead of eating more.

Now, some people, again, studies report averages. And there are individual data points. That's why there are some people who, at least anecdotally, report that exercise makes them hungrier. That is completely valid. It could be your beliefs about it, it could be a number of different things, but it's important to understand that there is individual variability. And I think one of the things I've learned to appreciate more is not trying to separate psychology and physiology. We do this a lot and say, well, I want to know the physiology, I don't care about its psychology. And now I'm appreciating more that psychology is physiology.

As with most things now, we have a kind of biopsychosocial model. And I'll give you an example of this. Many people get really caught up in appetite. And if we could just suppress people's appetite, that would be part of the problem. But people don't eat just because they are hungry, they eat for many different reasons, especially social reasons. So, can you remember the last social event you attended where there was no food? ANDREW HUBERMAN: No. LAYNE NORTON: Right. If you look at plates from the 19th century, they're that big. How big are the plates? ANDREW HUBERMAN: The whole buffet.

LAYNE NORTON: Right. ANDREW HUBERMAN: Yes. LAYNE NORTON: There are situational signals. You are sitting watching television. Oh, have some popcorn, have a snack, whatever. ANDREW HUBERMAN: I even see this with... you know, how one person picks up the phone and then everyone picks up their phone. I think there is a similar effect with food. LAYNE NORTON: Yes. And the same thing, right? Like, how many times have we done it ourselves or been experienced people who have said, oh, you should drink something, you should drink alcohol, especially, right? People... I was hanging out with someone last night and I had a beer and they only had water.

And I'm like, I don't feel the need to try to convince them to do that with me. You know what I mean? But as humans, we are wounded animals. We don't want to do something alone and isolated. I suppose this is a very tenuous belief of mine. But doing things alone and isolated during ancient times will set off your alarm system. Because if you don't have other people, you can't protect yourself. Usually things were done together in groups. And I think that's one of the reasons why we tend to be tribal in nature about a lot of things.

So the point is, on the list of reasons why people eat, I mean, I've gotten to the point where I think hunger really isn't even the main reason people eat. Stress, lack of sleep... ANDREW HUBERMAN: Boredom. LAYNE NORTON: --boredom. ANDREW HUBERMAN: Yes. LAYNE NORTON: Absolutely. So unless we can do something that addresses all of those things, there's a line of a review article - this review article that came out in 2011 is by a researcher named MacLean. And it's the best review article I've ever read. It was called biology's answer to diet: the drive to regain weight.

And I basically went over all the mechanisms of these adaptations that occur during fat loss diets and how biology's response is to try to take you back to your past. And I'm going to butcher the quote, but at the end of the study he said that basically the body's systems are integral, redundant, and well focused on restoring depleted energy reserves. And any attempt or strategy to lose weight that doesn't try to address a broad spectrum of these things is going to fail. And that's why when people say, well, just eat low carbs, don'twill be hungry. Look, people don't eat simply because they're hungry.

So I think I really like to try to get out of the box and think about these things. And especially, when you read some of the literature, I recently read a systematic review of people who successfully maintain weight loss, which I thought was really interesting. So they took people who had lost a significant amount of body weight and kept it off for, I think, three years. And he basically asked them questions and tried to identify common ground. And there were some things I expected, like cognitive moderation, self-control, and exercise. And then one of the things they said that I found really fascinating was pretty ubiquitous among people.

They said I had to develop a new identity. Do you know Ethan Suplee? ANDREW HUBERMAN: No. LAYNE NORTON: So Ethan is an actor. He's been on, remember Titans and American History X. ANDREW HUBERMAN: I certainly watched American History X. LAYNE NORTON: Yeah. So he was very big. He weighed about 550 pounds. And now he weighs like 230 and is on drugs. ANDREW HUBERMAN: Well, 5... he was what... LAYNE NORTON: 550 pounds. ANDREW HUBERMAN: Wow. LAYNE NORTON: And he... every time he posts on his Instagram about his training, he says, "I killed my clone today." And I asked him, is this what you're talking about?

Creating a new identity. And he said, this is exactly what I'm talking about. Because I had to kill who he was. Because there was no way he could make long-term changes if he didn't just turn me into a new person. Because I mean, and addicts talk about this. Like people who are alcoholics. They had to make new friends. They had to hang out in different places, because their whole life had been centered around this alcohol-related lifestyle. And in fact, I would argue that eating disorders or disordered eating patterns are much harder to overcome than other forms of addiction.

And you think about food addiction. Well, in a way, bulimia and anorexia are still addictions. You can't stop eating. For example, if you are an alcoholic, you can abstain from alcohol. If you become addicted to cocaine, you can abstain from it. You can never abstain from eating. Now imagine you say to a gambling addict: well, you have to play this slot machine a couple of times a day, but no more. As if that were really a challenge. So yes. It's just... like all of this, it's very important to be comprehensive in the way we deal with these things.

ANDREW HUBERMAN: Right. These are incredibly important points. And to my knowledge, I don't think anyone has described it coherently like you are doing here. It's very important for people to understand this because obviously, as a neuroscientist, I believe that the nervous system creates our thoughts, our thoughts and feelings are related to psychology, and therefore, of course, our physiology and our psychology are the same. It is bidirectional. Now, nowadays, there is a lot of interest in the brain, body and particularly the gut: brain axis and we can talk about that. But I really appreciate that you're explaining how these different variables exist.

Each one can account for a series of different things. Exercise clearly has a remarkably powerful effect, both during exercise in terms of calorie burning and overall health and biomarkers. And it's wonderful to know that it can increase sensitivity to satiety cues. I think that makes it, at least in my opinion, very high on the list of things that people should absolutely do. But there are other factors too. And the identity piece is fascinating. It also reminds me...his story also reminds me of David Goggins, who talks about his very overweight former self almost as if he were a different person.

And he uses language that I'm not going to use here. But you know what? I met David, I know him a little and he is all intense and motivated, like an extraordinary human being, just as he seems to be online. He's that guy. But it seems like he had to more or less kill an older version of himself and he continues to do so every day. And I think what's his point about this other guy that he does it through a similar process, the word "today" seems to really matter. It's not like you defeated this older version of yourself and then that person was buried and disappeared, you said, you know, today I killed my clone, and that's the way David talks about it too.

So this is a daily process. And I think this is not just a small detail in the time that you put all these things together. I think what you are describing is fundamental, because we can pull each of these variables and talk about each of them. But at the end of the day, we are a cohesive whole as an individual. I'm sorry. You were about to say. LAYNE NORTON: Actually, that gets into one of my favorite topics, which is, why is it so hard for us to lose weight but even harder to keep it off? Because of obese people, six out of seven obese people will lose a significant amount of body weight over their lifetime.

So why do we still have an obesity problem? They don't keep it off. Why don't they leave it like this? When you look at the research, basically what it suggests is that people think: I'm going to go on a diet and I'm going to lose weight, and they don't think about what happens afterward. It's like thinking if you have a chronic illness or are diabetic. You can't just take insulin once and be done, right? You have to take it continually, otherwise you're going to have problems. If you go on a diet and lose 30 pounds, great. But if you then go back to all your old habits, you'll be back to where you were, if not further.

You can't create a new version of yourself while dragging your old habits and behaviors behind you. So what I'll tell people is... because people say, well, I'm doing a carnivore diet or I'm doing this diet or that diet. And I'll say it's okay. Do you see yourself doing that for the rest of your life? And if the answer is yes, if you really believe that that's going to be sustainable for you and for a lot of people, low-carb diet, intermittent fasting, whatever, they say, I felt calm. I could do this forever. Excellent. If you're going to lose weight, you need to invoke some type of restriction, whether it's a nutrient restriction like low-carb, low-fat, a time restriction, intermittent fasting, any form of time-restricted eating, or calorie restriction. - macro tracking, whatever.

Then you can choose the form of restriction. So choose the form of restriction that feels least restrictive to you as an individual and also don't assume that everyone else will feel the same way because I made this mistake. While I follow things. And so I allow myself to eat a variety of foods, I allow myself to eat some fun foods. But I track everything and I can change my body composition and be healthy by doing so. Now, it's not difficult for me. Partly, I've been doing it for so long. But for other people, that's very stressful.

They don't want to... they say, well, I'd rather not eat for 16 hours. If it's easy for you, do it because the only thing that... there were a couple of meta-analyses on popular diets. And basically what they showed was that they were all equally terrible for long-term weight loss. But when they stratified them by adherence, none of them were better at overall adherence. But when they stratified people based on lowest compliance to best compliance, a linear effect on weight loss was seen. So really what it's saying is: what is the diet that will be easiest for you to follow in the long term and that you should probably follow?

And people...again, this is where I step back and take the 10,000 foot view. Someone will say, well, I'm going to do a ketogenic diet because I want to increase my fat oxidation and I want to do this. And they're talking about all these mechanisms and everything. And that's great. Can you do it for the rest of your life? Is this going to be something sustainable for you? And if the answer is no, you probably need to rethink what your approach will be. ANDREW HUBERMAN: Incredibly important message. Basically, that. If I could highlight...if there was a highlight or bold and underline version in the podcast space, I would highlight...bold and underline what you just said.

And for those of you who heard it, listen to it twice and then move on because it's absolutely key. I think it also explains a lot of the so-called controversy that exists out there. I think it also intersects with the placebo effect. I almost want to say: choose the nutrition plan that you think you can follow for a long period of time, ideally forever. And choose your placebo too, because there's a lot of placebo woven into each and every one of these things: intermittent fasting, keto. Probably even vegan vs omnivore vs carnivore. LAYNE NORTON: Well, they even talk about the diet: the honeymoon period where you go on a diet and you're excited about it and like you're very adherent, and then what happens with every diet without exception in the In research studies, once a few months go by, adherence just starts to wait and fade away.

ANDREW HUBERMAN: We're really talking about a form of relationship here. I don't say this to be ironic. We actually had a guest at the beginning of the podcast, Dr. Karl Deisseroth, he's a psychiatrist and a bioengineer at Stanford. Tremendously successful. Alaska award winner, etc. And he talked about love as kind of an interesting aspect of our psychology where it's a story that you co-create with someone but you live in the future of that story. When you pair up with someone who was about romantic love, there's this kind of mutual agreement to create this idea that you're going to live in.

So it's not just about how you feel at the moment, but also about projecting a lot into the future. I see many parallels with a highly functional and effective diet. And I love it. I'm not drawing this parallel artificially, I'm doing it because I think it ultimately comes down to what you said before, which is that the brain and our decisions about what we're going to stick with are tremendously powerful. LAYNE NORTON: I think one thing I will say is, keep in mind that when you look at the research data, the meta-analyses on, say, time-restricted eating versus nothing, when you compare calories, there doesn't seem to be a difference in weight loss, fat loss and most health biomarkers.

The same goes for low-carb and low-fat foods. Less fast calories and protein. Kevin Hall did a meta-analysis in 2017 where they looked at, and again, actual body fat loss. And another important point was that I think there were 22 studies on this. But they all provided food to the participants. That's important because that ensures that adherence can be much higher in those studies, whereas in various free-living studies you can sometimes see strange results. ANDREW HUBERMAN: People steal food secretly or just don't... LAYNE NORTON: It's very difficult... ANDREW HUBERMAN: ...eat the way the study would ideally have them eat.

LAYNE NORTON: Unless the person receives ongoing support, studies where a dietitian talks to people every week tend to have pretty good compliance. In other words, it is expensive to have done the study. And again, as what limits studies, money, money, money. But the low-carb versus low-fat, low-protein, and low-calorie diet equates, with basically no difference in fat loss. Now, some people get upset about this. But it's like... to me, that's... this is cool because you can choose the tool you want. One tool doesn't seem to be much better than another. So choose the one that works for you.

Whatever lever you have, you have a ton of different options. ANDREW HUBERMAN: You mentioned choosing something that you can stick to for a period of time. Is there ever a case for someone to say, look, I like to eat low carb or even keto for six months and then switch to a more standard omnivorous calorie maintenance diet and then switch back? Are there any disadvantages to doing that for health reasons or to lose weight over time, or to maintain weight over time? Because I realize that not everyone is trying to lose weight. And I definitely want to talk, at some point, about how to eat to maintain weight.

Because I think there's a significant fraction of people who are trying to do that. Yes. Are there any disadvantages to being an amateur? Keto for a few months and then omnivore for a few months, etc.? LAYNE NORTON: I think that's really cool, especially that you like, maybe, finding what you feel is easiest for you. But in terms of strategy, I mean, I guess, some people might take dopamine but, oh, switch and get something new. And you feel a little more positive about it. ANDREW HUBERMAN: And being a model partner. LAYNE NORTON: Yes. Yes. Exactly. So I don't think that's how I would normally set things up initially for someone, but if someone said, hey, I just like to have some variety and change it up, as long as they stay that way... their behaviors and they're controlling portions or You name it, and they're able to maintain a calorie deficit or, depending on what your goal is, I don't think there's really any downside to it.

I think the only thing to keep in mind is that,When we look at going between extremes, that is, low fat to low carb or vice versa, there can be, in that transition, a bit of a strange period for lack of a better term. Like, for example, if you've been on a ketogenic diet and all of a sudden you go to a high-carb diet, you're basically going to be insulin resistant for a short period of time. Now, is that going to cause any health problems? Probably not in the long term, especially if you're still watching calories.

But just because your body has upregulated these systems, dealing primarily with fat and glucose production rather than glucose metabolism, now if you start taking in glucose or carbohydrates again, like for example, they do to someone... or a glucose tolerance test afterwards. have been on keto, they will do pretty badly. But that doesn't last that long. ANDREW HUBERMAN: About how long? LAYNE NORTON: A few weeks. ANDREW HUBERMAN: I think it's important for people to know, because I have a feeling that those first few weeks is the period of time where a lot of people run back to what they were doing before.

Which isn't to say they shouldn't, but I certainly have. I tried a very low carb diet and I would have assumed, and now I know I'm completely wrong, but I assumed that I was so starved of carbs for so long that my insulin sensitivity, which is a good thing, the way you guys, would have reached the clouds, and could simply absorb every bit of glucose that it would have ingested through carbohydrates. So I actually changed. And I felt like I had some pretty terrible brain fog. I even had some nerves. And I thought, what is this?

My blood sugar was low before and now it should be in more moderate territory. But based on what you just said, I upregulated the enzymes and systems in the body for fat metabolism on the ketogenic diet and then I changed... basically there was an increase in the molecules involved in... presumably glycolysis. LAYNE NORTON: Transition period. I mean, think that if you haven't trained with weights before and you start training with weights, you're going to feel pretty bad. Like you're going to feel pain and stiffness and all that kind of stuff. But I will say that he's not necessarily wrong in what he said about being more insulin sensitive, because it depends on how you measure insulin sensitivity.

So if you measure with something like fasting blood glucose or fasting insulin or even HOMA-IR, these tend to be pretty good on a low-carb diet. But if you do all the glucose tolerance testing, it tends to be pretty bad. And then it depends on your specific measurement. So I think the idea that the ketogenic diet makes you glucose intolerant or insulin resistant, I think that's just a transition period. And I'm not too worried about that. But it is something important to keep in mind. And one of the reasons why if someone were to transition keto, typically, if I'm working with them or one of our trainers is working with them, we'll tell them to do it slowly and systematically. a period of four to eight weeks.

That way, hopefully, you won't have that two-week period where you're like, oh man, why do I feel so bad? ANDREW HUBERMAN: A very important point. I want to go to the other extreme literally and figuratively and talk about gut health, because so far, and certainly... LAYNE NORTON: I see what you made of that pun. ANDREW HUBERMAN: And certainly in the last few minutes we've been talking a lot about top-down processes. The brain, the psychology, the placebo effects, but the very real aspects of them, it's not that you can imagine 2,000 calories, 1,000 calories and somehow change the law of thermodynamics.

I can not do this. But we've been top-down in integrating many different ideas into weight loss and weight gain maintenance. But gut health, at least the most popular studies on gut health, have left a lot of things out of whack. For example, this idea that you can take obese mice and literally give them fecal transplants from lean mice, and yes, that sounds like what it sounds like. Fecal transplants are definitively introduced through the same end from which they exit. And I point this out because many people have asked me what... and it scared me a little, I thought, yes, it's not about ingesting feces, this is... they literally do a transplant of these from thin mice they become mice obese and obese mice become lean.

And yes, this has been done in humans. A limited number of studies observed some pretty impressive effects on weight loss that I have to assume could be related to the placebo effect. These obese people may have been told, hey, look, you're going to lose weight thanks to this fecal transplant from thin people. But most likely it had some effect on your core physiology. I don't know what aspects, although I can speculate what. And they became thinner. They lost weight. And that is, in a sense, miraculous, especially given the important role of psychology and exercise and satiety cues, because I'm going to assume that they controlled for several of those other variables, although no study is perfect.

What are your thoughts on gut health as it relates to metabolism, energy utilization, and balance? LAYNE NORTON: Yeah. So the first thing I'll say is I'm not an expert on gut health, but I will... I feel relatively comfortable talking about it based on conversations I've had with experts, one of them Suzanne Devkota. , what... - Do you know her? ANDREW HUBERMAN: Well, from what I understand, she's kind of a phenomenon in this area. LAYNE NORTON: So she was actually doing her master's degree when I was doing my PhD in the Lehman lab. So she was one of my lab partners.

ANDREW HUBERMAN: Fantastic. LAYNE NORTON: And the other thing to say is that even the gut health experts, and Suzanne will tell you this, they say she, she's talking to me in 20 years. We know very little. I think something that people don't understand in general is that the scientific consensus is moving very, very slowly, probably for good reason. Because if we simply reversed our scientific consensus based on one study, it would be a disaster. So it will be a while before we really understand the implications of the gut and what it means. So when it comes to weight loss, this probably plays a role.

I mean, we've seen that something is happening. Now, if that's something where a gut microbiome produces makeup that's more resistant to obesity, maybe you're extracting fewer calories from the food you eat. Or maybe it's raising your BMR. Although I think that's probably unlikely. ANDREW HUBERMAN: Do you think it might affect the way satiety signals are? LAYNE NORTON: So that's... ANDREW HUBERMAN: I mean, let's go back to the brain again. LAYNE NORTON: --so... we know there's a link in the gut-brain axis. So my suspicion is that it's probably working through appetite regulation. I mean, if you look at the most effective obesity treatments out there, which is like semaglutide, I mean, you consistently see an average body weight loss of 15%, which is huge and people don't gain it back.

It is a mimetic of GLP-1, which is an intestinal hormone. And basically, it's a very, very powerful appetite suppressant. ANDREW HUBERMAN: Well, I guess I'm interrupting, but I hope with a purpose. There is a really interesting study. And it is true that it is in mice, but it was recently published in a neuroscience journal. And basically, the bottom line is that, like so many things in neuroscience, GLP-1 works in two parallel pathways. In the brain, it appears to affect neurons in the hypothalamus that control satiety. So exactly what you are saying. And in the gut, it seems to create an activation of the mechanosensors in the gut.

So the perception is that the intestine is even fuller... or fuller. I have to say it's not bloated, because I think people who take semaglutide don't feel bloated. I don't know, maybe they do. But that one feels like your stomach is actually fuller because these mechanical sensors that send... stretching send signals to the brain, oh, actually I have some food. I'm not empty down there. LAYNE NORTON: Right. ANDREW HUBERMAN: Anyway, this result makes me happy mainly because every time I hear about a drug or a molecule that has an effect, we think that it has an effect in a certain place.

But it's interesting that, especially for something like appetite regulation, it would impact the body and the brain in parallel. Anyway, forgive me. LAYNE NORTON: That's great. ANDREW HUBERMAN: You can tell I'm very excited about this. And here you are telling a neuroscientist, me, that a lot of things, perhaps, go back to these brain mechanisms of satiety. LAYNE NORTON: Yeah. I mean, I think, and especially looking at the research on leptin, we used to think, okay, the metabolism is primarily based in the liver and then there's the metabolism in the adipocytes and the skeletal muscle. But none of this exists in isolation.

There is a lot of interference between these paths. And that's when we get into the mechanics, although one of the things I love the mechanics. But one of the things I tell people is to keep in mind that when it comes to a result, like when I say results-based, we're talking about physical results like weight loss, fat loss, changes in blood markers. , whatever. , although that is the sum of thousands of different mechanisms. So sometimes you can affect a mechanistic pathway and get a direct result, but not always. Every time you introduce a treatment or anything into the system, it's like throwing a stone into a lake.

Create waves. And we don't always know what they will be. And that's why... I mean, we've seen certain medications that work in this pathway. And then they list all the side effects. And you say, well, how would it create so many side effects? Because nothing... for the most part, they don't work in one place. There are many places where it works. And to your point about semaglutide and the effects on mechanical sensors, that's probably why many people report low-grade nausea when using semaglutide. That's why. Because if you're... that feeling is usually not a really comfortable feeling, but I mean, it will make you not eat.

So I think it's absolutely likely that there is a connection, but we haven't fully clarified how it works. And we think about how complicated the intestine is. I think I heard something like there are more cells in our microbiome than in our body. So we're actually more... in terms of a cell-by-cell level, we're actually more bacteria than eukaryotes. ANDREW HUBERMAN: There's Justin Sonnenburg, who is one of the world's experts on the microbiome. He's in the lab above mine at Stanford. And he has this idea: It's just an idea that, because we are more bacteria than cells, the question is: who is the host and who is the passenger?

LAYNE NORTON: Yes. ANDREW HUBERMAN: Maybe, we're just... maybe we're being exploited to bring them and interact, because they interact and grow with each other. And this idea of ​​this scaring people, Lex Fridman will love it. That maybe humans are actually the vehicles of the microbiome and not the other way around. Still, it's a scary thought. Do you do anything specifically to support your gut microbiome? Are you a probiotics, fermented food, or fiber guy? LAYNE NORTON: So, again, I'm going to go right along the lines of what I heard from Suzanne and other experts. So if you want to improve gut health, one of the most important levers (the three most important levers you can use is not eating too many calories and exercising) there is a connection between exercise, gut, and fiber.

That's right: from what we know, dietary fiber appears to have a positive impact on the gut because it is what is called a prebiotic. So that your intestinal microbiota can take in, especially, soluble fiber. Although there is actually some evidence, at least in mice, that they could also use some insoluble fiber. I think Suzanne was doing a study on hemicellulose and she saw that some, like specific forms of microbiota, flourish on hemicellulose, which suggests that they may actually be getting some kind of fuel from it, which is really interesting. But again, in mice... big warning. Then your gut microbiome can produce these short-chain fatty acids by fermenting soluble fiber.

And there is quite a bit of evidence that these volatile fatty acids, which can then be reabsorbed in the liver, have some positive effects. Such as butyrate. When they took butyrate supplements, they actually saw positive effects on insulin sensitivity. So what we seem to understand is that more diversity seems to be better, fiber seems to be positive, and prebiotics seem to work much better than probiotics. ANDREW HUBERMAN: Supplemented prebiotics. LAYNE NORTON: Yes. So the problem with most probiotics is that they generally don'tThey are concentrated enough to colonize. And even if you colonize, what happens is that, let's say, you colonize a microbiota that you didn't really have much of.

If you don't feed it adequate fiber, it won't stick around anyway, because it will essentially starve to death. So the research seems to clearly suggest that eating enough fiber, which is, again, a prebiotic, is a better way to have a healthier gut per se than the probiotic. ANDREW HUBERMAN: What fiber sources do you use? And I think... I mean, I realize there's a wide variety of options out there, but people will want to have some ideas about how they could, maybe, mimic what you're doing. LAYNE NORTON: Yes. And I would just say diversity. So there are various tests of different sources of fiber: fruits and vegetables, obviously, cereals, some whole grains, some cereals and then various other sources.

This is one of the things we really don't have a good idea about. If you know that this source of fiber is better than another source of fiber, we know that fiber in general is pretty good. And one thing I will tell people is that if you want a longevity hack, I mean, fiber is kind of a longevity hack. If you look at some of these cohort studies, there was actually a very large recent meta-analysis of over a million subjects. And basically, what it showed was that for every 10 gram increase in fiber, there was a 10% reduction in mortality risk.

And that extended, specifically, also to cardiovascular diseases and cancer. So one of the things I'll tell people when they're really wondering if it's intermittent fasting or all these other things, that's great, that's great. Are you eating more than 50 or 60 grams of fiber a day? ANDREW HUBERMAN: Conceptualize 50 or 60 grams. So if I ate like... let's say, a quarter plate of broccoli and the broccoli wouldn't be stacked to the ceiling. The broccoli is reasonably stacked there. How many grams of fiber are approximately? Yes, it's like two cups of broccoli. There's a lot. LAYNE NORTON: Yeah. So 200 grams of broccoli, per se, would probably be like 5, 6 grams of fiber.

ANDREW HUBERMAN: And do I need to receive how much per day? LAYNE NORTON: Well, I would say... ANDREW HUBERMAN: Ideally. LAYNE NORTON: Typically the recommended dose is 15 grams per 1,000 calories because if you eat few calories, it's hard to get enough fiber. But according to... and again, these are cohort studies. But unfortunately, randomized control trials in humans that last 20 years cannot be done. That doesn't actually seem like the high end, at least as far as the benefits of fiber go. It probably comes down to how much you can tolerate without feeling uncomfortable. Because if you're eating a ton of fiber, I mean, at some point, it's not going to be very comfortable.

ANDREW HUBERMAN: Yes. Exercise becomes uncomfortable or dangerous. Yeah. LAYNE NORTON: And I'm actually touching on that because I think it's important. A lot of people in the carnivore community have said, well, you don't need fiber, you poop fine without it. And I will always say, well, pooping is the last reason to consume fiber. Like yeah, help. It appears to make elimination easier, you can do it more frequently, and it adds bulk to your stool. But that's not why you should eat fiber. The reason you should consume fiber is because of the mortality effects. And part of the rejection will be, well, this is a healthy user bias.

And what I will say is... ANDREW HUBERMAN: I mean, healthy people do this and therefore it's working. LAYNE NORTON: Healthy people eat more fiber and therefore... ANDREW HUBERMAN: OK. Yeah. LAYNE NORTON: And I mean, yeah. There is something to that. But if this were simply a healthy user bias, you would typically see some disagreement between studies. And a great example of that is red meat. Therefore, not all studies show that red meat has an association with cancer and mortality. There are differences according to the population's consumption, according to what they define as high red meat, low red meat, whether it is processed or unprocessed.

But I haven't found a study on fiber, cardiovascular disease, cancer, and mortality that didn't show improvements with higher fiber content. To me, that suggests that effect is real. And again, I would try to do it with as much fiber as you can comfortably get because it seems to have really powerful effects and is good for the gut microbiome. The other thing that may be a consideration for the microbiome is that there is some evidence that saturated fats may not be good for the microbiome. Which reduces the prevalence of some of the most positive strains of bacteria.

And that seems to be due not so much to the saturated fat itself but to the bile end products that, combined with saturated fat, seem to have a negative effect on some of these healthier forms of gut microbiota. But again, this is really difficult because we don't even necessarily know yet which species of gut microbiota are positive or negative. And that's... I mean, this goes into some of these studies where they might call it dysbiosis. It sounds scary, but dysbiosis simply means that the gut has changed. ANDREW HUBERMAN: Right. LAYNE NORTON: It doesn't necessarily... it doesn't say anything qualitative about whether the change was good or bad.

And I think these are just things that we need to keep in mind when we talk about these things. That this is still in its infancy. But in terms of big levers, I mean, it fits pretty well with what we know about a healthy lifestyle. Exercise, don't eat too much, get a good amount of fiber from a variety of sources. ANDREW HUBERMAN: Fantastic. Great because it fits what I like to think of as the center of mass of evidence. And I'm starting to get a sense of what your process is around selecting studies and no study is in its entirety, but when you look at, as you mentioned, all the studies on fiber that have a positive effect to some degree or another. another, It's quite difficult to refute that there is nothing really interesting there.

LAYNE NORTON: And one thing I will tell people is, a study... I mean, sometimes I change my opinion based on a single study when it's really well done and very powerful. But usually a study moves me a little bit. And then maybe, if another one comes out, maybe a little more. And then, very slowly, I'm going to get some... I mean, my experience with LDL cholesterol, that's something I changed my mind about a while ago. When I was younger, around 2005, going into graduate school, the predominant thought was, well, it's not so much the LDL, but the ratio of LDL to HDL, that's what matters.

And probably about five years ago, and I was pretty firm in that opinion, and then five years ago, looking at these Mendelian randomization studies, I said, I can't hold this position anymore. ANDREW HUBERMAN: What is your revised position on LDL? LAYNE NORTON: If you look at the research, HDL is important because it's a marker of metabolic health. If you have high HDL, it suggests that you are quite metabolically healthy. Very rarely you will have high HDL and high CRP, which is an inflammatory marker, or dysregulated blood glucose. Almost exclusively, people who have high HDL will have good biomarkers of metabolic health.

But if you take medications that raise HDL, it doesn't reduce your risk of cardiovascular disease. In Mendelian randomization studies, Mendelian randomization basically uses natural randomization. So some people, in the case of HDL, naturally secrete more or naturally less HDL secretions. And we talked about how... you can't really do a randomized controlled trial on 20-year-old humans. And when you try to look at something like heart disease, I mean, it's a lifelong exposure problem. It is very unlikely that differences between treatments can be detected in two or even five years. I mean, people don't develop... normally, they don't develop heart disease until they're in their 50s, 60s, 70s.

What Mendelian randomization allows is to say, okay, we have these people who naturally secrete more or less. Then we can stratify them and look at what their risk is. So if you look at people who have low HDL versus high HDL who retain some of the other consistent key variables like LDL, you don't really see an effect on heart disease. ANDREW HUBERMAN: From LDL. LAYNE NORTON: From HDL. ANDREW HUBERMAN: Got it, okay. LAYNE NORTON: But when you look at LDL and lifetime exposure to LDL, it's like a linear effect on heart disease. And we know that it's actually not so much LDL, but more apolipoprotein B.

But that tends to coincide with LDL in general. And if you look at the mechanism... I mean, we know that LDL can penetrate the endothelium, so there's the mechanism. If we look at the epidemiology, it supports that it is an independent risk factor, and then again, these Mendelian randomization studies where we can look at people's exposure over a lifetime, and then we see that dose-dependent linear effect. For me, that was compelling enough to change my mind on that particular topic. And then if you look at some of the Framingham data, look at the high levels, if you want to stratify, like high HDL versus low HDL, both groups look at high LDL and low LDL.

So if you have high HDL and low LDL, you will still have a lower risk factor than someone with high HDL and high LDL. ANDREW HUBERMAN: So proportion does matter. LAYNE NORTON: The ratio improves. The same goes for inflammation. If you look at people with low inflammation and low LDL, they will be at lower risk than people with low inflammation and high LDL. Again, that was enough to change my mind. But it was necessary... it was as if not only one study came out. It was, OK, then there was another study, and then another study, and then another study, and at a certain point I said, OK, well, now, either I have to change my mind or, basically, I'm just going to be cognitively dissonant and say, No, I don't believe in all that.

And I think that's one of the things to keep in mind. People will say, oh, are you saying this is a bad study? I will very rarely call something a bad study, because data is just data. But the question is how it is presented and how widely it is applied in mainstream media or by fitness influencers. And what I'll do is try to step in and say, OK, let's consider x, y, and z as well. And so it's not a bad study, but let's be careful how broadly we apply the interpretation. ANDREW HUBERMAN: Yes. Well, and I think you're in a unique and important position to be able to put things in their proper context because of this, for lack of a better word, a holistic view of how the placebo effects of psychology and Central physiology are related to each other. .

Etc. In fact, I think your training as a biochemist and then your training in nutrition with someone who... Don Lemon, who pushed you to focus on results, I think is a beautiful capture of the continuum in which you can observe something. . Because for those of you who don't know a lot of laboratory studies in mice and humans, for example, in the field of biochemistry or in vitro studies, you will see that a change in some molecule can be quite dramatic. . And then the assumption is, oh, just take... take the drugs that will change that molecule in a particular direction, and then you'll get the effect that you want at the whole organism level.

The person will lose weight, the person will gain muscle, the animal will not have Alzheimer's, etc. But it just doesn't work that way because of the redundancy and this interaction. LAYNE NORTON: Well, a great example of that is that my research was done in rodents. All my studies on protein metabolism and leucine, in particular, is what we were studying. Well, we know that if you give leucine, it increases muscle protein synthesis. But we also know that if you supplement with leucine, people don't get more muscular. ANDREW HUBERMAN: I was just about to say... LAYNE NORTON: As always...

ANDREW HUBERMAN: --all you have to do is supplement with leucine? LAYNE NORTON: Right. Well well. And then how is that possible? Muscle development is not just protein synthesis. It is also the balance between synthesis and degradation. And it turns out that degradation is very, very difficult to measure. But it's a great example... and again, one of the interesting things about my PhD was that it actually changed the way I ate, which I think is interesting. So before I was like, I eat eight meals a day, I eat every two hours, I try to keep... ANDREW HUBERMAN: Eight meals a day?

LAYNE NORTON: Yeah, when I got to grad school. ANDREW HUBERMAN: To get those 30 grams of protein per meal? LAYNE NORTON: The idea was to put that amino acid in, right? Like just having an IV hooked up for amino acids. ANDREW HUBERMAN: Not really, folks. LAYNE NORTON: Not really, yeah. But that was the concept. But in the first study I did we basically saw that many people had measured the amplitude of protein synthesis in response to a meal. We wanted to see how long this lasts and where it peaks, right? And then my thought was, okay. Well it will probably be traced with leucineI mean, if I had to pick one food that I could eat, even though I'm not a pure carnivore, for the rest of my life, it would be that because, I think, it would get me where I need to go and then I'd probably have to take in some fiber.

LAYNE NORTON: Yes. ANDREW HUBERMAN: But it's an excellent point. I have a question that I don't want to get off track on, but I hope it's related enough that you can answer it now. In the context of this, if I'm going to eat, say, 2 grams per kilogram of body weight protein and I'm not eating multiple meals, maybe eating two or three meals a day, I'm certainly going to be eating more than the 30 threshold. grams that has been talked about for a long time, we can only assimilate 30 grams of protein per meal. Should I just not worry about it?

Some of it will go to the thermic effect of food, some of that could be converted to glucose through gluconeogenesis. So should I be worried about this 30 gram limit? Because I think that by balancing the body weight threshold of 1.6 grams per kilogram with the number of meals, with the need to exercise and work and live my life and sleep, etc., very soon you run into obstacles where you just You can't do it or you're spending a lot of time trying to focus on it. LAYNE NORTON: You can't optimize all things at the same time. ANDREW HUBERMAN: You would lose your mind and your body.

So what is necessary in terms of frequency if one is consuming enough protein? And then related to that question, is there any reality to this idea that if you eat one meal a day or are fasting and then eat, say, 200 grams of protein in one sitting, you can take in more because you were starving for protein? . Is that a real thing? LAYNE NORTON: So most protein studies are done after fasting because to test them with stable isotopes, you need to be in a stable state. So we haven't observed that. It does not seem that fasting really allows you to assimilate more protein after a fast.

So this gets to the core of one of the things I looked at in my PhD, which is: does protein distribution matter? Because most Americans get between 65% and 70% of their protein at dinner. Breakfast tends to consist of foods with a minimal level of protein. ANDREW HUBERMAN: Does any culture actually eat a big breakfast and not a big lunch and dinner? We all heard that that was ideal. We'll get into circadian timing in a moment, but does anyone really do that? Steak and eggs for breakfast and then taper off the rest of the day? LAYNE NORTON: I know German culture tends to have a big breakfast, but it also tends to have sugary foods and all that.

As for the teleological, I'm actually not sure about that. So if you look at that, you consider that the protein doesn't really have a storage mechanism. People will say, well, lean tissue is a storage mechanism. That's like saying a house is a lumber yard. Yes, if the house is made of wood, you can get wood from it, but that is not what it is built for. You are building the house based on a demand. The same goes for muscle tissue. There is a free reserve of amino acids, but it is very, very small. So when we consider things like fat, which basically has unlimited storage capacity, carbohydrates, with relatively large storage capacity, we can store 400 or 500 grams of carbohydrates between the liver and the muscles.

And then protein, which has almost no storage capacity, the idea that, well, you could make up for a lack of protein in one meal by consuming too much of another meal didn't make sense to me. So in one of the studies that we did, and again in rats, both groups were consuming whey protein, meaning a high-quality protein, they were getting exactly the same amount of calories, exactly the same amount of nitrogen, exactly the same amount . macros. Everything was the same. The only difference was that one group basically received three meals with similar amounts of protein. Dinner was a little bigger because we wanted it to be something similar to how people eat.

But each meal would exceed the threshold to stimulate muscle protein synthesis. While in the other group I built it so that the first two meals of the day did not stimulate muscle protein synthesis. It should be below that threshold. And then the last meal accounted for about 70% of your total daily protein. And so we made them eat for 11 weeks. And I will never forget this. That's how obsessive I became, there were 110 animals in the study, I made all the diets and weighed exactly every meal for every animal for 11 weeks. So I was there at 6:00 a.m. m., I was there at noon and I was there at 6:00 p.m. m.

ANDREW HUBERMAN: I love it. That's the kind of PhD student professors dream of. You seem like a dream student. LAYNE NORTON: So at the end of 11 weeks, we looked at lean body mass, we looked at body fat and hind limb weight. We didn't really see a difference in lean body mass, but what we did see was a difference in hindlimb weight. It wasn't huge, but there was a significant difference in the size of the hind limb muscles of these animals. So it's interesting that there was no difference in lean body mass. And what we found, at least with the liver, the animals that we ate in a high protein meal, they actually had larger livers, not like a huge amount and it's not something that I would consider unsafe, but it was a proportion statistically significant. difference.

And for me, at least, since I'm trying to explain that there's not a difference in lean body mass, but a difference in hind limb weight, maybe there's some sequestration of... that's driving the protein synthesis of the splenic system. tissues instead of... because you're limiting skeletal muscle protein synthesis. And we do know that splanchnic tissues are more sensitive or have a higher rate of protein synthesis per day. For example, the rate of skeletal muscle protein synthesis in humans is approximately 1% per day. So it takes about 100 days to recover skeletal muscle. Whereas, just like your entire intestine, your entire GI will turn around in about two to three days.

Actually, and the liver also has a very high amount of protein synthesis, which is one of the reasons. It is actually one of the most metabolically active organs. So, all that to say, it's not: there has been a human study that showed something similar. And then there were a couple of others who didn't. And then in the studies of intermittent fasting, which is maybe a good tool to consider compared to continuous feeding, one thing I will say is that it is similar to the 16/8 style of intermittent fasting. There have been a couple of studies with Grant Tinsley.

And this is something I've also changed my mind on. Grant Tinsley has done a couple of studies where they used the 16/8 protocol. They made them train during their feeding window and made them eat. I think there were at least three protein-containing meals during those eight hours. ANDREW HUBERMAN: These are humans? LAYNE NORTON: These are humans. And they saw no difference in lean body mass at the end of the study compared to people who ate as many times as they wanted throughout the day. Now, if you look at some of the more extreme forms of fasting, like alternate-day fasting or 2/20 or 4/20 fasting, there are some studies where you're starting to see differences in lean body mass.

So my suspicion is, and I'm just guessing. So this is tenuous. My suspicion is that probably if you eat two or three high-quality protein meals a day, you'll get the vast majority of protein benefits. The most important thing is to get enough total. And then secondly, try to consume at least two or three meals with high-quality protein. But if you're pretty extreme with fasting every other day or maybe just one meal a day, then I think there may be some effects on lean mass. body mass. But again, these can also be mitigated if you do intense resistance training.

Typically, that's the biggest factor in terms of lean body mass. Yes, protein distribution can make a difference, but I'm trying to put it in context so people don't feel the need to go out and eat four meals a day. But again, what I would say is that some of the gentler forms of time-restricted eating seem to be fine for lean body mass; Now, the warning is the following. One of the nice things about animal studies is when you consider: if you want to have a large number of subjects, a high level of control over a long period of time, it's pretty much your only option.

So in our research review reps, I created a Venn diagram, which is basically like three intersecting circles. One is the duration of the study, another is the level of control and the other is the subject number. And for those three circles to intersect, it almost has to be that of an animal. ANDREW HUBERMAN: Right. And REPS, is it a newsletter or a book? LAYNE NORTON: This is our monthly review of the research. That's why every month we review about five studies that come out about fitness and nutrition. We usually do at least one nutrition, one workout, and one supplement a month.

ANDREW HUBERMAN: We'll put up a link where people can register. Is this a registration format? Excellent. LAYNE NORTON: Yes. So it's a subscription-based service. Basically, when people look at my study, well, why did they see differences in muscle weight while some of these other studies don't see differences? I weighed each meal for 11 weeks and keep in mind that 11 weeks in the life of a rodent is a really long time. That's about 1/8 of its total lifespan. So is there no effect or is the effect relatively small and would take a long time and a very high level of control to see in humans?

I don't know. But I think what I would say with relative confidence is that if you're going to do 16/8 intermittent fasting, you're probably fine. Especially...and again, what's the point? For example, if you're a bodybuilder looking to be the biggest person possible or you're a soccer player or you're in some field where having as much lean body mass as possible is really important to you, then I would say Well, in You're not actually gaining much by eating any type of time-restricted diet. ANDREW HUBERMAN: I think most people listening to this don't fall into that category. LAYNE NORTON: Right.

ANDREW HUBERMAN: I think most people want to maintain or lose weight. Maybe they would like to add a little bit of, quote, shape or muscle to specific areas of their body and lose body fat. LAYNE NORTON: Right. And I think your normal forms of time are restricted, and you're probably perfectly fine for that. And again, I don't want anyone to think, well, I fast every other day, there's no point in resisting training because I'm going to lose muscle mass. No no no no no. You can still build muscle doing that. You may not build as much muscle as you would if you ate in a more traditional format.

But if that's something that works for you and your goals, and especially, if it's about losing fat or controlling your calories, then again, it's about the hierarchy of what's important. So to answer your question, I think time and frequency matter a bit; not so much the frequency, but rather the distribution. So I think distribution matters, but it's a much smaller lever than just getting enough total protein. And as for animal versus plant, I used to be in the camp that there is no way anyone could build that much muscle on a plant-based diet. And now I think I've said again that it can be done, it just requires a little more planning.

And I don't want to say always, but it is very difficult to do without an isolated source of protein. So unless you're going to supplement with an isolated plant source of protein, it's very difficult to get enough without exceeding your total calories because you can calculate that, especially, like the case of someone who may be on calorie restrictions, trying to get enough protein. . from whole intact plant sources. So you have a few different things working against you. First, the protein sources you consume also contain carbohydrates and/or fats. Two, it is a less bioavailable form of protein, and three, it is a lower quality protein in terms of generally having less leucine, fewer branched chain amino acids, and fewer essential amino acids.

ANDREW HUBERMAN: Answer the question that I almost interrupted you with, which was: does it come down to the leucine content? And it seems that that is one of the components. And that many of the vegan and vegetarian sources of excellent protein, that excellent vegetarian or vegan protein source, are packed with calories from carbohydrates and/or fat that make it difficult to stay below the caloric threshold. While a steak is... I'm not... and obviously, people might want to avoid it for ethical reasons.LAYNE NORTON: Sure. ANDREW HUBERMAN: But that's a completely different matter. But a steak or a piece of chicken or an egg is... well, an egg has a yolk, which is fat.

But it is almost a pure source of protein and fat. No carbs for the trip. LAYNE NORTON: Right. So I guess what I would say is you can do it. It requires a little more planning. And you're almost always...if you're vegan, especially, you're going to be better off eating something with some isolated form of protein or a vegan form of protein. Now, this word comes to people who say, well, what about limiting amino acids and that kind of thing? It's a consideration. Some of the best forms of vegan protein in terms of amino acid content are like soy.

Now I hear everyone online screaming about their testosterone levels. In terms of actual results and testosterone, there was a recent meta-analysis that looked at soy. And I think if it's your only protein source, then maybe the dosage is high enough to cause some strange effects. But if you only use it once or twice a day, it doesn't seem to have any effect on testosterone or estrogen. It can be a decent source of protein, because it is a complete protein source. It has a PE cause of one, which PE cause is basically a measure of the quality of the protein based on: does it provide enough of all the amino acids so that none are limiting?

So soy is one of the only vegan sources that does that. Interestingly, potato protein isolate actually has a similar essential amino acid content to whey. So Potato Protein Isolate. It's really hard to find. ANDREW HUBERMAN: Interesting. LAYNE NORTON: I've been trying to find... ANDREW HUBERMAN: But vegans take note, vegetarians take note, because... or rather, vegans, because whey is vegetarian, and whey is a very high protein. quality in terms of... LAYNE NORTON: Very high quality proteins. And actually... they're now creating serum from... I think it's... I may mischaracterize this. But I think they are able to produce it from yeast or something.

ANDREW HUBERMAN: Incredible. LAYNE NORTON: That's... so for vegans, this is a great option because you can have whey that's not animal-based and it's going to be just as good as animal-based whey. So I think that's great. Coming to leucine... let me go back, sorry. So another reason why using an isolated protein can be useful is because it is also more bioavailable when isolated. When protein is bound to actual plant material, it tends to be less bioavailable. Now, cooking can help increase bioavailability because it breaks some of those bonds and everything. But it still seems to be lower.

And you don't... it's really interesting. There was a recent study where they compared a corn, wheat, and pea protein blend to whey. And basically, the result was that 30 grams of each stimulated protein synthesis to a similar degree. But the plasma amino acids of the plant-based protein have not yet reached as high levels as those of whey. Now, that might just be... it doesn't matter because once you reach a certain level, you get all the benefits. But I still found it interesting that they didn't go that high. The other thing to consider with vegan protein sources is the leucine content.

So one of the studies we did was looking at wheat, soy, egg, and whey. Isonitrogenated, meaning we equate protein between groups, isocaloric, we equate calories. And we analyze muscle protein synthesis. And I think this was...the meals came from 15% of the total energy from protein. Just like the protein level of your food pyramid. And we saw that in the wheat and soy group, they did not increase muscle protein synthesis, but the egg and whey group increased muscle protein synthesis. Now, the really interesting thing is that we went back and took wheat and added free leucine to it to match the leucine content of the whey and the protein synthetic response was identical.

Again, I don't like to oversimplify things, but leucine seems to really be driving this ship. And I'll never forget, Layman called me into his office one day and he was always doing these thought experiments...he liked to think about why something happens the way it does. ANDREW HUBERMAN: Dangerous territory. LAYNE NORTON: Yeah. Then he would say, one day, I'll never forget, he said, Layne, why do you think the body evolved to just detect leucine for muscle protein synthesis? And of course, I'm like, I don't know, man. I just work here like. I'm just trying to get my PhD.

And he said, well, think about it. You would want something that really wasn't extensively metabolized by the intestine and liver, because you would want to show up in the blood at values ​​that reflect what you just ate. Makes sense. And you would want it to have passive diffusion through the muscle cell because you want it to be concentration dependent, and it is. So... ANDREW HUBERMAN: Access the tissues and cells that need it most. LAYNE NORTON: Right. So not having active transport, but passive transport. So yeah, I thought it was really interesting the way he explained it.

There are very few different options for vegans. You can use an isolated source of protein. And again, like there are some good options coming, because this plant-based whey is going to be a great option for people. You can add free leucine, whatever your protein source is. ANDREW HUBERMAN: Simply with supplemented leucine powder. LAYNE NORTON: It tastes horrible now. ANDREW HUBERMAN: Yes. I think I've heard that. Maybe you've even tried it. LAYNE NORTON: It's completely non-polar, it doesn't dissolve into anything, and it's gross. ANDREW HUBERMAN: Can it be put in capsules? LAYNE NORTON: You can put it in capsules.

Yes. Then you could take a capsule. For example, if you are eating your normal meal, you can simply take one capsule of about 1 gram of leucine. It will probably push you enough that you're ready to go. And then there are options like mixtures, especially with corn. Corn is actually high in leucine. That is a percentage of its protein. Now, you have to remember that if you eat corn on the cob, you're going to get like 2 grams of total protein. So it's not that much leucine. But if you isolate the protein, put it into powder, well, now when you get like 80%, 90% of the weight now is protein, corn is actually about 12% leucine in terms of protein.

Therefore, it is a great source of leucine, but is almost downright deficient in some other amino acids. But you can mix it with some other protein sources. For example, you could mix it with soy or peas and create these complementary blends that would actually have quite a bit of leucine, but also some of the other essential amino acids. So there are options for people who consume plants. And I mean, we've seen people who consume plants build impressive amounts of muscle. There are quite a few bodybuilders who are plant-based. ANDREW HUBERMAN: And a lot of endurance athletes like it.

And although... when we talk about muscle, we often think about building muscle. Resistance performanceSports. And also just performance for the typical person who does some cardiovascular training, hopefully some resistance training. Also and just living life. I mean, it seems like a lot more people are vegan now or at least avoid meat, particularly red meat. I'm not one of those people. I limit the quantity and certainly focus on the quality of what I eat. But I eat red meat, which brings me to a general question in terms of food choices: can we do a relatively brief summary of the following?

Tell me if this is correct or not. That's what most of us should focus on, for the sake of health and life expectancy, on eating minimally processed and unprocessed foods. Maybe even cook our own food. Now I realize that that is heresy. But ideally we would do something like that. And really try to avoid highly processed and high sugar foods. And I'm using this as a transition to get into a question that I really want your answer to. I'm dying to ask you this: If sugar intake isn't actually increasing as much as people think, why are people getting so fat?

So what do you think of a blanket statement that we should try to eat foods that are low or no, minimally or unprocessed, in about 80% of our foods? Is that a reasonable number? LAYNE NORTON: Yes. It's actually difficult to get completely unprocessed foods because almost everything goes through some type of processing. ANDREW HUBERMAN: So I'm thinking about anything that doesn't survive long without refrigeration... LAYNE NORTON: On the shelf? ANDREW HUBERMAN: Yes. On a shelf, like an apple or a banana. So, I eat oats, I eat ground oats for me, as long as there's not a lot of other stuff and they're minimally processed.

A steak is not really processed, although the animal is cut, etc. So there are some steps there. But that's what I mean. LAYNE NORTON: Yes. ANDREW HUBERMAN: Yes. LAYNE NORTON: And I think everyone gets the gist of it. I'm probably a bit pedantic when it comes to these things. ANDREW HUBERMAN: No, this is good. Actually, one of the things I appreciate about you is something that people close to me make fun of a lot, which is the warnings and the insistence on accuracy is really important because, especially with online communications these days, It's like a runaway train.

People... LAYNE NORTON: It's very easy to misinterpret what you're saying. ANDREW HUBERMAN: It's very easy to misunderstand. And misinterpretations are often used to harness completely new ideas about what is true and what is not. Mainly about what is true. So I really appreciate the nuance. And this is what a long-form podcast really allows us to do: catch every curve, you know? LAYNE NORTON: I agree 100% with what you said. That if you were going to take a broad brush, that trying to focus on minimally processed foods is very important. The only caveat I would say is that I think it's important to understand why.

Because otherwise people can make this weird association that if I eat minimally or any processed food, it will kill me. Or like every time I eat it, it's like I'm smoking a cigarette and my health... my longevity is declining. According to the studies we have, it is mainly about energy. That processed food simply makes people eat more spontaneously. And Kevin Hall demonstrated this in his study that was very... I mean, he designed some of the most elegant studies in nutrition. ANDREW HUBERMAN: That's great. LAYNE NORTON: And they basically took people off a diet of minimally processed foods and then gave them access to ultra-processed foods.

Very few instructions. Just eat until you feel satisfied. And they spontaneously increased their calorie intake by 500 calories per day. I mean, that's huge. And we haven't fully figured it out yet. People say, well, it's sugar. It doesn't seem to be sugar in terms of simple insulation. Well, they are fats. They do not appear to be fats in isolation. Well, it's the combination of sugar and fat. Partly, well, it's the combination of sugar, fat and salt. Partially. But there's a kind of general magic in the texture and the mouthfeel and just the general palatability of things. That's why I always say that there are right and wrong ways to these different diets.

Like, for example, there's the right way to do it plant-based and then there's what's in some of these documentaries where they eat plant-based macaroni and cheese. And again, I love a good macaroni and cheese, but that shouldn't be formed, shouldn't be presented as a healthy diet. just because it is "plant-based." Because I mean, you're eating a highly processed food that's very tasty and easy to overeat. Same for keto. Now you have keto ice cream and keto cookies and all this kind of stuff. And I'm like, yeah, and if you look at them, they actually have more calories than the regular stuff.

And I'm like, yeah, this is completely missing the point here. Like you're actually taking it yourself - the whole point of those diets is that the reason you tend to lose weight originally is like having good luck 10 years ago, going on a ketogenic diet and eating processed foods. Like you just can't do it, really. Now you can. But the problem is that it's not going to work because you're still going to consume too many calories, because even if it's keto, what are they doing? Well, they're trying to make it more palatable, they're trying to make it have a better mouthfeel, which, I guess, if you're being keto for the sake of being keto, great, but if you're hoping for body composition. modification, it is going to have a really negative impact.

So yes, I think it can be important to minimize the amount of processed foods you eat. That being said, it depends on the individual and their goals. If your goal is, for example, to build muscle or maintain a weighttall body for a sport, like an NFL offensive lineman or something like that, or if you're... I worked with an NBA team, they were like... I can't reveal anything, but they were considering drafting a certain player. And, just like for them, processed foods can actually be a tool. ANDREW HUBERMAN: Or a teenager. I think we all want young people to eat healthier.

Develop good habits. But some of them, their caloric needs are so high... LAYNE NORTON: Very high. ANDREW HUBERMAN: --that if they ate what I eat, they would dissolve... they would just waste away. LAYNE NORTON: I describe this, again, with a financial example. It's like a budget. So if I make a million dollars a year, for example, is it okay for me to buy a $100,000 sports car? Let's assume that loans do not exist. Is it okay for me to buy a $100,000 sports car if I can still pay my mortgage, pay my utilities, and take care of my responsibilities, the things I need to do?

Is it okay for me to do that if it makes me feel good and is fun? ANDREW HUBERMAN: That's fine with me. LAYNE NORTON: Yeah. It's fun. Like it fits your budget. If I make $50k a year, should I go out and buy a sports car? Probably not, because I'm not going to be able to pay my mortgage and all these other responsibilities. So your protein, your fiber, your micronutrients. These are your responsibilities. But they become much easier to achieve when you have more calories. So if you're eating 4,000 calories a day for whatever goal you have, you'll probably have some left over, and you'd like good luck eating 4,000 calories of minimally processed foods, frankly, you'll be miserable because you're going to have such intuition that you'll feel like you can't even move And again, now okay, well, is there something inherent to food processing?

Is there anything that we can distinguish and know, okay, well, this is going to have a negative effect on health, even leaving aside body composition issues? And I would say there's not much evidence of that so far. And a great example of that is sugar. I mean, I actually just wrote a very long article on my website about why I think sugar was not the root cause of the obesity epidemic. And you mentioned that sugar intake over the last 20 years has actually decreased a little bit. ANDREW HUBERMAN: Alcohol consumption, well, if we look at it as a whole, it might have increased a little bit, but certainly in the male sector it has decreased a lot.

It used to be... it was 5 o'clock. People drank all day. People smoke much less. I think it's a real puzzle. I'd love to know what your hypotheses are. LAYNE NORTON: Well, smoking might actually be the opposite because nicotine is actually an appetite suppressant. ANDREW HUBERMAN: Appetite suppressant and also increases concentration. The problem is that it often arrives in a delivery device that can kill you. LAYNE NORTON: Yes. ANDREW HUBERMAN: But nicotine itself is a powerful agent. It may also not completely compensate for age-related cognitive decline, but it makes the brain work better. LAYNE NORTON: I have a friend who doesn't like caffeine.

And he just takes those nicotine pouches and basically takes one almost all day because he thinks he has a very stressful job and he's a high performer. ANDREW HUBERMAN: Yes. You have to be careful when administering it, but there is a Nobel Prize-winning neuroscientist who chews five or six pieces of Nicorette an hour, which I don't recommend, but when he stopped smoking, he just couldn't function as well. . And he was the one who recommended that I write literature on how to compensate for age-related cognitive decline. Even the maintenance of neurons, and it's quite interesting. LAYNE NORTON: Well, to be honest, it's a pretty impressive nootropic.

Now, the first thing to keep in mind is that when we talk about consumption data, these are basically based on actual production. They assume that we are producing this amount of these foods, so we can assume that consumption will follow that amount. So it is not a direct measurement. But it has been validated in a few different studies. We know that oil consumption has increased. That's the way it is. That's one of the big ones. And this forms the crux of... seed oils are like the root of... ANDREW HUBERMAN: That's definitely the question I'll ping you on.

LAYNE NORTON: They're going to come into your house and kick your dog and hit your mom and all kinds of things. And I'm happy to address them. So the calories have still increased. There are some people who claim that they have become stagnant. I think the data seems to suggest that calorie intake continues to increase. And the other thing to keep in mind is that even if it has plateaued, it is still at a high enough level that obesity will probably continue to increase to a point where it will probably plateau if calories have plateaued. ANDREW HUBERMAN: What about energy production?

Leaving aside NEAT, because that sounds very individual, I mean, people, people we know, focus on exercise. But there are many people who don't exercise. LAYNE NORTON: And energy production has declined over the years. I mean, it's very obvious when you look at how people work now compared to 30 or 40 years ago. It's very different. ANDREW HUBERMAN: Walk less. Also, I recently learned that high school kids don't take physical education classes in many schools. But we had to get dressed and run and get dressed. And if you didn't bring your change of clothes or didn't wash them in which case it would be better if you didn't wear them, nothing like the smell of a boys locker room after a weekend, I still remember it. and it's not pleasant.

But you had to run and do push-ups with everyone else or play volleyball in your normal school day clothes. So I understand that physical education is no longer part of basic education. LAYNE NORTON: It probably depends on the state, but I know a lot of states have eliminated it just because of budget cuts. ANDREW HUBERMAN: So activity is decreasing and caloric intake is increasing. Maybe... LAYNE NORTON: Stagnating a little bit, yeah. ANDREW HUBERMAN: --maybe stagnating. Is that enough to explain the obesity epidemic? LAYNE NORTON: Based on what I've seen, I think that's enough. ANDREW HUBERMAN: So maybe it's not such a mystery after all?

LAYNE NORTON: No, I don't think it's much of a mystery. I think people don't like the concept of energy balance, and I think because they insert judgment into it, which is, okay, if you're gaining weight over time, at a fundamental level, it means that you're eating... you're consuming more energy than you expend. People insert the judgment, which is, you're lazy, you're lazy or whatever. And I think there are a lot of people who actually think that, in fact I remember talking to someone who said to me, well, I would never hire an obese person for a job because it's obvious that he's lazy.

And I just remember going, are you serious? There are many very, very intelligent, high-achieving people who are obese. And as if it weren't... this is what happens when you just put people in buckets. People are much more complicated than this. Yes. There is some personal responsibility. But then when you look at the data and take it, there was a study done on obese women where they found that obese women were 50% more likely to have had some type of sexual assault trauma in the past. We know that people in low-income areas are more likely to be obese.

I think there are several people who have a higher ACE score, which measures traumatic childhood events. I think there was a study that shows they are more likely to be obese. So there's... yes, it's an energy imbalance problem, but just saying, eat less, move more, is like saying to broke people, well, just make more money than you spend. It's technically correct, but it's very useless. What is most useful is to describe and implement the habits and behaviors that will allow them to achieve this. Then I realized we got off track a little bit, but back to sugar, around 2005, I think sugar was fattening and bad for your health, regardless of any other variables.

So independent risk factor. And again I want to be very clear what independent means. Independent means independent of all variables. This is bad for health and body composition. ANDREW HUBERMAN: On its own, regardless of whether or not, for example, it increases hunger and appetite. LAYNE NORTON: Right. Or caloric intake. She was at a graduate school reunion. And one of the professors was someone who had done research on high fructose corn syrup and also fructose specifically. And she was talking to another professor and she had done this study on rodents where they had been fed like... I think 60% or 70% of their calories came from fructose.

And they saw some really strange things happening in the liver with lipogenesis and all that kind of stuff. And the other teacher says, yeah, it's pretty obvious that high fructose corn syrup makes you fat. And this professor who had done this research said, yes, because people overeat. And he says, don't you think there's something inherent to it? And he said, no, I think it's just calories. People are eating too many calories. He said, we did a proof of concept to see if we could... try to eat 70% of your daily calories from fructose. You can't actually do it.

High fructose corn syrup contains only 55% fructose. So if you ate nothing but high fructose corn syrup, you still wouldn't reach the level they fed in this study. That made me question my beliefs on the matter. So I looked back and said, Okay, look, let's get the epidemiology out of the way. It's not that epidemiology is useless, but people who consume more sugar are likely to also consume more calories. So I looked for randomized controlled trials where they equalized the calories and varied the amount of sugar. And it doesn't seem to make any difference. At least for fat loss or gain...

ANDREW HUBERMAN: But what about health? So, for example, if someone... and I know someone like that who loves sweets, is thin, do some exercise, not a lot. But my concern is that a significant fraction of their calories come from these sugary foods and therefore they are not getting enough fiber, maybe protein, etc. LAYNE NORTON: Let's look at the epidemiology for a second and then I'll address this more directly. When we look at the epidemiology, people who consume higher amounts of sugar tend to be more obese and tend to have worse health biomarkers. People who eat fruit, a lot of fruit and sugar, don't have those same associations.

So why is that? Well, because fruit contains fiber. Then I began to believe, based on the data I was analyzing, that high sugar consumption was not the problem itself. The problem was that foods high in sugar are generally very low in fiber. But if you get enough fiber, is sugar a problem? There was a classic study by Surwit in 1997. I think it is still the best study today that looks at this. And I know those people who say, well, it was made in 1997. It's irrelevant. You know, I know, if it's a good study, it's a good study.

ANDREW HUBERMAN: Some studies are timeless. In fact, they have greater relevance... LAYNE NORTON: You're not going to go back and undo the discovery of DNA because it was 60 years ago or whatever. ANDREW HUBERMAN: No. LAYNE NORTON: So they looked at an 1100 calorie diet, meaning a low calorie diet. One group consumed more than 110 grams of sugar, such as sucrose, per day. The other group consumed about 10 grams of sugar a day. Calories, proteins, carbohydrates and fats, all combined. And they provided all meals to these participants. Very strictly controlled. And it was more than six weeks. Both groups lost exactly the same amount of body fat.

Therefore, body composition in terms of sugar per se does not seem to matter. Then they also looked at some health biomarkers like blood lipids and blood sugar and some other things. Again, there were no real differences. The only difference was that all of their biomarkers improved in both groups. The only real difference was a small difference in LDL. So, the low-sugar group had a slight improvement in LDL. But that's probably because they were consuming more fiber. And we know that fiber can bind to cholesterol and lower LDL cholesterol. So now I want to warn you about this.

Sugar probably has no positive health effects. So there's that. And nutrition is an exchange. If you eat one thing, you don't eat another, right? So what I would tell people is to probably focus less on the sugar and more on the fiber. So if you eat 30, 40, 50, 60 grams of fiber a day, but your sugar level is 80, 90 grams, I wouldn't worry as much, especially if you also watch your calories. What I would worry about is if you're only eating a decent amount of calories and you're not getting enough fiber and overall, right? And even in studies, there are some meta-analyses that look at theisoenergetic exchange of different carbohydrates with sugar carbohydrates.

So fructose, glucose and sucrose. Now why is this important? Well, again, if they're not equal... when I say isoenergetic, it means equal in energy, equal in calories. Basically, when you swap out sucrose, glucose, or fructose for other forms of carbohydrates, do you see differences in these health markers? Like HbA1c, fasting blood glucose, and blood lipids, with rare exceptions, and I don't remember all the data points exactly. But the bottom line is that it really doesn't seem to make a difference? Now, for anyone, my argument is the straw man, I am not defending sugar consumption. But I think it's important for people not to create strange associations in their minds because one of the things I've observed, especially in the fitness industry, is when people feel like they can't eat something;

It's one thing if let's say, I choose not to eat this just because I choose to. But it's very different when you intentionally restrict because you feel something is wrong. And this... I mean, you know, the human brain is, in many ways, amazing and, in many ways, really dumb. So when you intentionally try to restrict something, what tends to happen is that you're more prone to binge eating. So people who will try... well, I'll never eat sugar again, or I'll try to limit sugar. And this is not the case for everyone. But it has actually now been shown in studies that people who deliberately restrict a specific nutrient tend to crave more of that nutrient.

And if they're exposed to it, they're more likely to have what's called a disinhibition reflex, which is basically a compulsive response. Because the idea is: well, this is bad and there is no context about the dose of the poison. This is just bad in general. So if I have it I've already screwed up. You might as well have everything you want. And I like Spencer Nadolsky's comparison to this. That's like getting a flat and then going out and cutting the other three tires because you might as well do that. So I really... I try to come from that perspective: I've seen a lot of people struggle with, maybe, not an eating disorder, but disordered eating patterns because of these associations that they've made in their mind.

And that's why I'm so pedantic and rigorous in saying: Okay, yes, it's a good idea to eat mentally processed foods and try to avoid them. But not because processed foods are bad per se, but rather what tends to be the result of excessive consumption of processed foods, which is excessive calorie consumption and therefore energy toxicity that contributes negatively to health. ANDREW HUBERMAN: Yes. It seems like, again, it comes back to the possibility of positive, negative or neutral behavior change. And the perceptual change like the desire to eat as long as you can is terrible. It is a terrible state.

And I think this is a perfect transition for something that first brought us together, which was this artificial sweeteners thing. And let me, for the record, be very clear. I have been eating foods with artificial sweeteners for a long time. So throughout grad school, I didn't have the best habits. They are healthier now than then. But I would have one or two Diet Cokes a day. I still have a Diet Coke from time to time, I'm not completely averse to drinking something with artificial sweetener. Although I avoid sucralose for reasons I can perhaps get into a little later.

But many of the things I eat contain stevia, which is not artificial but is a non-caloric or low-calorie vegetable sweetener. And I don't have any problem with that. I became very interested in artificial sweeteners because of the animal data that points to the idea that they can alter the gut microbiome, and then altering the gut microbiome, as you pointed out, is a very broad statement. We don't really know what percentage of lactobacillus, exobacilius, or whatever ilium it contains (they all seem to end in ilium) is ideal. And in fact, many of these companies that hire people send their stool samples to analyze the microbiome.

I mean, take note, we don't really know what a healthy microbiome looks like, but we do know what an unhealthy microbiome might look like. And it's one that doesn't have a lot of diversity there. So I was interested in that, then there's the recent human study that we should definitely get into. But what interested me the most were artificial sweeteners because they have this conditioning effect on food. And you see it in animals and in humans, that if you ingest it... well, coffee is a very good example. The coffee doesn't really taste good, although I like it.

But when you first try coffee, most people think it's bitter and disgusting. Most, like 95% of people say, this doesn't taste good. LAYNE NORTON: Wine and beer are the same thing. ANDREW HUBERMAN: Yes. But people have learned to associate the state with taking caffeine, which most people like just to feel normal, right, caffeine is one of the few drugs that we take just to feel enough ourselves. so that soon, myself included, we will really want and enjoy a cup of coffee. In my opinion, it is a powerful example of the conditioning effect of food. So it's like a Pavlovian thing.

Instead of salivating, you crave. LAYNE NORTON: Right. ANDREW HUBERMAN: And it seemed like this study from Dana Small's lab, which was certainly a small study (no pun intended in itself, not many subjects), showed that if you ate artificial sweeteners along with foods that contained glucose, maybe you could even Over time, you'll get a greater glucose response from artificial sweeteners alone. You and I connected through this study on social media. You pointed out that the design and study were not great. There was co-consumption of glucose, which complicated things. We can go deeper into that. But the reason I'm talking about all this context is that artificial sweeteners are many things.

So I'd like to talk about their effects on blood sugar in the acute sense and depending on what we might be ingesting them with and how they might be changing blood sugar regulation at the brain and/or body level. And then I think the gut microbiome data is interesting enough to discuss. And I have changed my opinion on artificial sweeteners based on what you have taught me. So this is a case where I've completely changed my view, which is that, now, I don't have a problem with them based on current data, which doesn't mean I'm drinking a full cup of sucralose, but I do.

I feel good eating a little stevia and some aspartame and I don't worry too much. LAYNE NORTON: Yes. So I think, taking a broad view, we have to think, again, about the hierarchy of importance. And what are you replacing with? Therefore, there is no situation in which it is not a net positive result to take someone who drinks sugar-sweetened beverages and have them drink an artificially sweetened beverage. In the meta-analysis, there was actually a recent network meta-analysis that looked at markers of adiposity, HbA1c, a bunch of different health markers, and when you substitute those, we're going to call them non-nutritive sweeteners and stevia is not artificial.

But when you replace sugary drinks with NNS, you see improvements in many different things. What was really interesting about this network meta-analysis was that they also looked at substituting water for sugary drinks. And the effect was not as powerful as... and these are randomized controlled trials. ANDREW HUBERMAN: So drinks that contain artificial sweeteners are more beneficial. LAYNE NORTON: They were better for adiposity, for improving adiposity, and then on health markers, it was kind of a washout. Water and drinks with non-nutritive sweeteners had a similar behavior. But obviously there were better drinks than the sugary ones. Then they built on: A network meta-analysis is where you can compare things that weren't directly compared.

Therefore, there are not many studies that directly compare NNS with water. But if you have a common comparator, then if you compare A to B and B is compared to C, you compare A to C based on how they interacted with B. Cut it out a little bit, but that's the crux of a network meta-analysis. . So they compared NNS to water and found that NNS was actually slightly better at improving adiposity. ANDREW HUBERMAN: ENNs, of course, are non-nutritive sweeteners. LAYNE NORTON: Right. ANDREW HUBERMAN: Yes. LAYNE NORTON: Now, again, if you like to drink water and you don't want to...

I'm not trying to convince anyone to do it. What this seems to suggest is that these artificial sweeteners or non-nutritive sweeteners have a small appetite suppressing effect. Now, this gets a little more complicated because if these were people who drink sugary drinks, they may have already developed a sweet taste. and try to resort to water, it is too big a leap for them. And then having something like intermediate is a little bit better. There are many things involved in this. But these are randomized controlled trials, which are a little more tightly controlled, and I tend to default to them a little more than epidemiology, whose epidemiology is so confusing, because sure, consumption of non-nutritive sweeteners can be associated with different things, but there is also a completely different set of lifestyles and habits that are related to that.

So I tend to hang my hat a little more on randomized controlled trials. So understanding that. OK. Now, all things being equal, I understand that this is a tool that may help some people, and every time I post about non-nutritive sweeteners in the comments, there are always one, two or three people who say, all I did was delete The drinks. . And instead I drank diet soda and lost 50 pounds. Or I lost 75 pounds. I even had 1%. I lost 100 pounds. That's the only thing I did. ANDREW HUBERMAN: Wow. LAYNE NORTON: I mean, it's a pretty huge lever to pull.

If you consider someone who might be consuming five or six Cokes a day, we're talking about a lot of calories. ANDREW HUBERMAN: And that also means that by replacing it with drinks that contain artificial sweeteners, they didn't replace soda with food. LAYNE NORTON: Right. So now let's talk, shall we? This is where we can get into the microanalysis, but is that obese person the one who lost 100 pounds doing that? Do I really care about, perhaps, a small alteration in her gut microbiome? No, because their gut microbiome is actually much healthier now that they've lost all that excess adipose tissue.

Again, the classification of what worries me may change depending on the specific situation. Now, let's take someone like me, who is thin and doesn't really have any health problems that I know of. What about artificial sweeteners for me? Well, in my case, I started using them because of bodybuilding contest prep, because it was the only appetite suppressant that worked for me. But do I think they are healthy? Probably not. Do I think they are unhealthy? I would say that based on current data, I don't think they are harmful to health. Now, the information about blood glucose.

So some of the problems with some of these meta-analyses or these reviews is that they lump all the non-nutritive sweeteners together and then they can say, well, there's no effect on this or there's an effect on this. Well, the problem is that these are different molecules and they can interact differently. Aspartame, very clearly, appears to have no effect on blood sugar or insulin. This has been proven repeatedly. Stevia doesn't seem to have much of an effect. Saccharin and sucralose, the jury is mixed. Now, there was the study that we first linked to where, I think, their primary outcome measure was actually they were looking at sweet taste.

Like how it affected the sweet taste. So what they did was the group receiving sucralose was also combined with maltodextrin. The control group received sucrose, which is an appropriate way to compare sweet taste because maltodextrin is not as sweet as sucrose. So when you try to combine sucralose, which is already sweet, with another form of carbohydrate, you'll want something less sweet compared to your control. But for the outcome measure of insulin and blood glucose, it's probably not as appropriate because we know that maltodextrin has a much higher glycemic index than sucrose. ANDREW HUBERMAN: So they adequately controlled the flavor, but not the effect of the sweeteners.

And I think that was a key component. And I think, yeah, the part of that study that intrigued me was actually a spoken word version because that study led me to see a talk that, and hopefully, we'll have Dana Small on the podcast at some point. - was that they had children do this study. And they actually had to stop the study because a couple of the kids became prediabetic. I mean, it seemed like there was something dangerous... this was Yale School of Medicine. It's a good place. I mean, there's a range everywhere. But it seemed like there was something about the sweet taste that, if taken to the extreme, could affect blood sugar.

This hasimpacted my behavior. And I try to avoid really sweet things unless they are exceptionally delicious or the occasion calls for it because I think they increase my cravings for sweet things. LAYNE NORTON: Well, it may not necessarily be a craving, but it just programs you. Your taste buds are extremely adaptable. Take, for example, Indian food. If you bring Indians to America and ask them to eat some of our food, they will think it tastes extremely bland because they are used to food so spicy that unless they have a certain level of spiciness, they will barely be able to taste it.

If you've ever been on a high-sodium diet and then gone on a low-sodium diet, you'll feel very bland. ANDREW HUBERMAN: That's where I started. LAYNE NORTON: But over time, your taste buds adapt. So sweet it's the same. If you are used to eating a lot of sweets, you become desensitized. And then if you opt for something less sweet, it may taste bland at first. Over time, it will get better. So I think it's one of those things that, again, depends on the situation. If someone is obese and says, well, this will help me eliminate sugary drinks, why would you want to take that tool away from them?

That's a great lever to pull. I mean, if someone can literally lose 100 pounds with just one lifestyle change and that's not even that inconvenient of a change, that's powerful. But again, is this the healthiest thing they could do? And I think that's what they usually ask. We do not know. Is it healthier than water? It's probably not as healthy as this one. Who knows? But I really give all those warnings because you don't want people to be able to use this as a tool to think, well, no, I can't do this because it's actually bad for me.

If it helps you lose 50 pounds or 75 pounds or whatever, trust me, it's not bad for you, right? ANDREW HUBERMAN: Well, it seems to increase your satiety signals. What do you think about the effects of the microbiome in this recent study? Because I think the recent study had some interesting features. And you have made a detailed description of the study. So for those who want that... LAYNE NORTON: Is this the two-week study or the 10-week study? ANDREW HUBERMAN: Yes, the two-week study. Yes. And we will provide you a link. You made a great video on your YouTube channel that really breaks down each piece.

But they compared the various artificial sweeteners and looked at the glucose response, looked at the microbiome and a number of different measures. What was your overall conclusion? And this was in humans, I think it was the first time the microbiome was observed in humans because of artificial sweetener. LAYNE NORTON: There are some studies on the microbiome in humans with artificial sweeteners. The first two that came out showed practically no effect, but they had a slightly shorter duration. It was two to four weeks. And again, it depends on what bacteria are being measured. There are many different types of bacteria, so they could simply be measuring one that didn't change.

And then a 10-week study came out that got a lot of press. And they showed... I think it was sucralose. Believe. They showed a changing effect on the gut microbiome. Now, the interesting thing is that when I went into the species that changed, the species that changed the most compared to the control was a species called... I'm going to figure out the name, but it's like Blautia coccoides, I think it's called . ANDREW HUBERMAN: I have to say that for those who work on the microbiome, it's very difficult to pronounce. I mean, you need a nomenclature and acronyms committee.

I'm sorry. Do it. LAYNE NORTON: ANDREW HUBERMAN: Enough. You are killing us. LAYNE NORTON: We'll call it BC. We call it BC. ANDREW HUBERMAN: BC, thank you. We're going to start the nomenclature committee without you if you don't do it soon. LAYNE NORTON: So you noticed that this increased three to four times. So I went down the rabbit hole with this. Interestingly, that particular species of bacteria is actually associated with lower adiposity and better insulin sensitivity. And obese people and obese children tend to have less of it. So I said, well, based on that study, you can argue that maybe sucralose actually improves the gut microbiome.

Now, I repeat, I am not making that claim. Because we have a hard time understanding what a healthy microbiome looks like. In this latest study that came out, my biggest take home was that I think it's safe to say that some of these non-nutritive sweeteners are not metabolically inert. There are some effects. Now, I think it has not yet been fully elucidated whether these effects are good, bad or neutral. Now I focused more on the blood glucose responses in my analysis. So in that 10-week study, they did an oral glucose tolerance test. And I didn't really feel like your conclusion fit your data.

So their conclusion was that, and again I think it was sucralose, it raised blood glucose. And this is where the statistics can get a little complicated. So my conclusion was that the area under the curve, the incremental area under the curve, which looks at basically the entire glucose response, was not different between the control group and the sucralose group. For me, that's the biggest benefit. There was one time point at the end of the study in the sucralose group, the 30-minute time point, that was statistically significantly higher than the control group. It's one of those things where I go, okay, it was a one-off moment.

It is statistically significant. But even then, we've seen statistically significant things end up being data artifacts because they don't replicate. So I'm not saying that's what's happening here. But again, the overall area under the curve was no different. So, for me, that was the biggest takeaway. ANDREW HUBERMAN: And we should probably mention that articles are published because of the effects, generally. Lack of effect, more difficult to publish. LAYNE NORTON: The null hypothesis doesn't... it's actually really unfortunate because a null hypothesis is just as useful information as the non-null hypothesis. But you are correct. There is a very strong publication bias towards showing an effect or not.

ANDREW HUBERMAN: Yeah, unless you can completely turn a field around by showing that something didn't happen, usually the positive result outweighs the negative result, positive means you see a result. And then, of course, it's a study. And... LAYNE NORTON: Yeah. ANDREW HUBERMAN: I think, as you mentioned before, the center of mass of data in a given field is probably the best basis for what we should do in terms of... and that's why I'm not going to change my behavior around the intake of artificial sweeteners. Personally, I will continue to consume stevia and aspartame in relatively small amounts.

LAYNE NORTON: Yeah. ANDREW HUBERMAN: But now I'm thinking, well, okay, if something has sucralose in it, maybe I don't have to actively avoid it. Whereas before I was. I was actively avoiding him. LAYNE NORTON: I thought the new study was very elegant... very complicated. I mean, to be honest, some of the animal stuff they did was extremely impressive. So actually the study had two arms. One was the human arm. One was the animal's arm. I focused much more on the human side. Basically, this was a two-week study. And the really unique aspect of this, which I think is both a strength and a weakness, was that almost 1,400 people applied for this study.

And I think they only had 120, who really got into it. Because they did a very detailed dietary analysis of these people. All of these people said they avoided artificial sweeteners or did not consume them. And I think people don't realize how ubiquitous sweeteners are. ANDREW HUBERMAN: Before the study, these people were like... it was like jury selection. They never... LAYNE NORTON: Yes. ANDREW HUBERMAN: It's like never having heard the plaintiff and the defendant. These are these mutant people who have never consumed an artificial sweetener. LAYNE NORTON: Right, so the strong point is that now you don't have a lot of pre-existing effects that could cloud what would actually happen when you add it.

For example, if you have people who are already consuming artificial sweeteners and then if we make them consume artificial sweeteners, the probability of things changing is pretty low, right? So I think that's a strength. It is also a weakness. And I want to be very careful because I think people took my words too far, which means I probably didn't do a good job of being nuanced enough. Here there is the possibility of a placebo effect. So to me, if someone has gone through so much pains to avoid artificial sweeteners, they probably have a preconceived notion that they are bad for your health, because they are hard to avoid.

Yes, it is possible that if they eat a minimally processed diet they simply are not exposed to them. And that is also very true. But the other thing the researchers acknowledged is that they couldn't blind the study. Because if you've never had an artificial sweetener before, you're just used to regular sugar and you have an artificial sweetener, you know? ANDREW HUBERMAN: You prove it. LAYNE NORTON: You know. Still sweet. But it's not the same candy. ANDREW HUBERMAN: And there's an interesting effect there, where a lot of people don't like the taste of aspartame the first time.

I actually stopped drinking diet soda for a while. I thought I should, and then I had one. It really tasted... I can only describe it as some kind of artificial chemical substance. And very soon it tasted delicious again. LAYNE NORTON: Yes. ANDREW HUBERMAN: So there's some attenuation there. And whether that is central or not, that is, within the brain, or peripheral, I don't know. But very interesting. Well, I think you play a critical role in defining what it is and what it isn't, which still needs to be determined in terms of this landscape and the whole nutrition landscape really.

LAYNE NORTON: And that study changed my opinion in terms of, okay, I think now we can clearly say that they are not neutral. Or sorry, they are not inert, right? That was the thought process before, it was fine. They're not digested or anything, so they must be inert. That doesn't seem to be the case. But again, when we look at the blood glucose data, there's... and I'm not saying this is what happened. I want to be very clear. I'm not saying this is what happened. I'm saying this may have happened. And that's why we need more studies to verify it.

If these people had a preconceived notion that artificial sweeteners were bad for them, it is possible that, knowing that they were ingesting artificial sweeteners, they could have had a blood glucose response. Now, my response to my own point would be that we should have expected to see it in all non-nutritive sweeteners, which we didn't. It was only on sucralose and saccharin. ANDREW HUBERMAN: Yeah, it was kind of a gradual effect, where sucralose and saccharin showed the most dramatic change. LAYNE NORTON: Yes. ANDREW HUBERMAN: And stevia and some others don't. LAYNE NORTON: And the other issue I picked up, maybe it's a matter of timing, was that their primary outcome measure was blood glucose, the oral glucose tolerance test.

But they had people administer their own oral glucose tolerance tests, which they basically gave them - they said, "Okay, drink this drink." And they were wearing continuous glucose monitors, which should have been fine. But again, for me... and I'm being in bad taste. And again, I know that all studies are limited by funding. So I think overall this was a great study. But I would have liked to see them monitor oral glucose tolerance tests to administer it. ANDREW HUBERMAN: Yes, and what they did before or after. You want to know if they didn't ingest this or they ingested that.

LAYNE NORTON: Right. ANDREW HUBERMAN: Yes. LAYNE NORTON: Those two things. But another caveat is that it was a two-week study. So we have to be very careful how much we interpret into this because it's also possible that this is a transient effect, right? And maybe it will go away with time. We do not know. But then again, I think we can clearly say that it's not inert, right? Now, no matter how much emphasis we put on that, in a two-week study, I'll still say: Okay, maybe if you're worried, don't do sucralose. But if you are 100 pounds overweight and want to use some sucralose as a substitute to help you lose weight, I would say don't let this study stop you from doing so because the net effect will still be more positive.

You don't lose weight, right? So if it's a tool that helps you, that's fine. But I keep open the idea that, well, this could also have negative effects. But again, we're looking at what the overall outcome is. And then they looked at some of the different things that were increased with these different sweeteners. And again, this word gets confusing because one of the things they saw was a huge increase in butyrate production due to the change in the gut microbiome, presumably. Well, as we discussed earlier, butyrate is actually associated with positive outcomes in terms of insulin sensitivity, inflammation, and a few other things.

Sothat I want to be very cautious before people say, well, if there's a change in the microbiome, it must be a bad change. We do not know. It's possible. And again, if 10 more studies come out and start showing this, then I'll start to change my personal opinion on artificial sweeteners. ANDREW HUBERMAN: Before I sat down today, I solicited questions on social media. And one of the questions that got a lot of upvotes, I like it so to speak, was one that I think raises interesting questions about short-term and long-term health. And it is the following. I think it's a common scenario.

Many people want to know what is the healthiest way to approach rapid weight loss. And here what I think is happening is that someone has an event coming up or is simply tired of having the weight they have, of carrying the amount of adipose tissue they have. And they wanted to know whether or not it's safe to, for example, lose three pounds a week for a few weeks before a wedding or some other event and whether direct calorie restriction and increased activity is the best way to approach it. that, with the understanding that they can recover a little later.

I think the ideal would be to keep it afterwards. But what do you think of that approach, of cutting your caloric intake in half, for example, and then doubling your physical output as well? LAYNE NORTON: It's interesting because you might be surprised by what I'm about to say, which is that the research data actually tends to suggest that obese people, who lose a lot more weight early, are more likely to keep it off. , which seems a bit contradictory, right? Well, that doesn't seem very sustainable. But again, you're weighing competing things. Then there is the sustainability aspect.

But there is also the fact that the acceptance of sustainability is huge. So a lot of people who are overweight or obese, if they start a diet and don't see something quickly, they quit because it's not working. Whereas if they see some quick results fairly quickly, they become even more committed. So I think the conversation, especially if there are trainers or trainers out there, is to just present that as... one of my favorite lines is that there are no solutions. There are only compensations. I think Thomas Sowell said that. So you're having a tradeoff here. Yes, you will lose fat faster.

You may also lose lean mass a little faster, which can be a problem. But I will say that the more adipose tissue you have, the more aggressively you can diet without negative consequences. Someone like me who diets really aggressively is not going to be good for my lean mass. First, I have higher than normal lean mass. Two, I have less body fat than normal. As body fat decreases, the percentage of weight loss from lean mass increases. So people who are very obese, because they have so much adipose tissue to draw from, there is very little reason for the body to metabolize lean tissue.

Now, that being said, if you continue... people misunderstand, like, well, I did a body scan or a DEXA and I lost 2 pounds of lean mass, and they lost 20 pounds total. . Well, keep in mind that adipose tissue itself is 13% lean mass. So there is actually a protein component to the structural component of adipose tissue. And it has some water. So it's about 87% lipids. But the other part is lean. So, at a minimum, you should expect a 13% reduction in lean mass when you diet. And then when you think about it, you lose overall body water, which registers as lean mass, and you lose that splenic tissues may shrink a little bit.

Therefore, it is normal for the average person to lose 25% to 30% of the weight they lose due to "lean mass." But that doesn't mean skeletal muscle tissue. And again, the more adipose you have, the more aggressively you can approach the diet without really negative long-term consequences for your lean mass or your overall health. But balance that with: Okay, if I'm going to do this, I need to understand that I'm not going to do this diet forever. I'm doing this to give myself a boost at the beginning. And at some point I have to accept the transition to something that is a little more sustainable.

ANDREW HUBERMAN: Based on what you just said, it reminds me of the satiety signaling effect of exercise that you mentioned earlier, that exercise can improve our sense of when we've had enough to eat. I just want to briefly mention that when Alia Crum was on the podcast, she mentioned that they had been doing a study that... I have to pair you two up and listen to the conversation like a fly on the wall. Because what she was telling me was that if people believe that a food is nutritious for them, eating less is considered more satiating.

Whereas if people see dieting as a system of deprivation, like, oh, dieting is hard, and the food sucks, and it's terrible, well, then they crave all kinds of other things. Whereas they actually observe in their studies that people report a reduction in craving if they are told, for example, that a chicken breast and broccoli and a little olive oil and rice are quite nutritious. In fact, it's very good for you. So people eat that. And they feel like they've actually eaten more. The satiety signal increases. So it's just a point that Alia raised. That's not my data.

LAYNE NORTON: Satiety is so impressive because even the pace at which you eat and even the size of the plate and the color of the plate, the color contrast... ANDREW HUBERMAN: Really? LAYNE NORTON: I don't remember exactly. I think if the plate is a similar color to the food, I think people eat more. While if it is a greater contrast, they eat less. So even the color of the plate can make a difference in how much you eat. Again, the human brain is very amazing, but also very dumb in some ways, right? ANDREW HUBERMAN: It's not an optimized algorithm.

LAYNE NORTON: I always joke with people. I say, just look at how stupid humans are. You put some water in front of them, like the ocean, and they say, oh yeah, I'll pay 10 times more for this. But we are connected that way. ANDREW HUBERMAN: Reward signaling pathways in the brain work primarily with one chemical, dopamine (there are others, of course) and very few algorithms. It's kind of like...intermittent reinforcement is random reinforcement. But in the end, there are not many algorithms. And we're probably not optimized, certainly not optimized for our own health because people will eat themselves to death, drug themselves to death, etc., simply because something felt good at some point.

This proves your point. LAYNE NORTON: Right. One of the things I tell people (I said it on someone's podcast) was, interestingly, that the dichotomy of life is that if you do what's easy in the short term, your life will be difficult. If you do what is difficult in the short term, your life will be easier. It's very strange. And in fact, Ethan Suplee had a great example of this. When he weighed over 500 pounds, he said, the amount of work he had to do to build a life he could live was a lot more work than simply going to the gym for a couple of hours a day.

He says the work in the gym is hard. He says, but when I look back and see how much work I had to do to maintain that lifestyle compared to just going to the gym and restricting calories, he says, maintaining the lifestyle of weighing 500 pounds was infinitely harder than what I do now. . And again, great example. In the short term... difficult. Go to the gym, calorie restriction. In the long run, life is easier. It's a really interesting dichotomy that I think about a lot. ANDREW HUBERMAN: And it can't be said enough. Seed oils. People want to ask about seed oils.

And for... LAYNE NORTON: Cut. ANDREW HUBERMAN: And for those of you who are listening and wondering why we're already laughing, I should mention that both in the Twitter sphere and on Instagram and online, there are very polarized points of view where it's probably not worth to focus. too long. But there are several people who maintain that seed oils are the source of everything: the obesity epidemic. LAYNE NORTON: Everything. ANDREW HUBERMAN: --inflammation, etc.-- LAYNE NORTON: Illuminati. ANDREW HUBERMAN: --everything. And then there are those who would argue just the opposite, that meat is the source of all problems, etc.

And I think through your nuances and experience, we've hopefully framed things appropriately so they're never so black and white. It just isn't. LAYNE NORTON: Rarely. ANDREW HUBERMAN: Rarely. I love olive oil. I realize that doesn't exactly fit into the seed oil category. I love olive oil. I use it sparingly. I also eat a little butter in moderation, etc. But is there data on seed oils? And here, I think a good example would be canola oil, which comes from rapeseed, which literally came to be called canola oil because rapeseed oil is not good marketing. LAYNE NORTON: No, no.

Not quite. So the first thing I will say is that seed oils have contributed negatively to our overall health because people over the last 20 or 30 years, what they have tended to add to their diet that increases the total calorie load is oil, mainly of seeds. oils. But when we look at 1-to-1 replacement with other fats, if we look at the epidemiology, yes, we can find some epidemiology that shows that people who consume more seed oil have more negative health outcomes. The problem, again, is tied to a multitude of other behaviors. And then you can find mechanisms.

And the idea is, well, they're polyunsaturated, which means that in the fatty acid chain there are multiple double bonds, and those double bonds can oxidize when exposed to heat and some other things. So the idea is, well, when you cook with these things, they oxidize it. And that's going to cause inflammation in your body. So that's a plausible mechanism. So, as always, I refer to the randomized controlled trials in humans. So what you tend to find is that when you substitute polyunsaturated fats for saturated fats, it's neutral or positive in terms of the effects on inflammation it's basically neutral.

There are some studies that show a positive effect of making polyunsaturated fats. But it probably depends on each polyunsaturated fat. And that's the other thing that's difficult because you're categorizing everything into this one group. And there are some differences between individual fatty acids. Even with saturated fats, for example, stearic acid does not tend to increase LDL cholesterol. While saturated fats as a whole tend to raise LDL cholesterol. But there are some saturated fats that don't. Again, we are putting things in buckets. And it's a little more nuanced than that. Then, if we look at the effects of polyunsaturated fats on markers of cardiovascular disease, again, it tends to be a neutral or positive effect when polyunsaturated fats are substituted for saturated fats.

Now, if we want to talk about monounsaturated versus polyunsaturated, there is quite a bit of disagreement between the studies. What I would say, based on randomized controlled trials in humans, is that it's probably better to consume monounsaturated and polyunsaturated fats instead of saturated fats. But again, if the idea is, well, that means polyunsaturates are good for me, so I'm just going to put a bunch of oil on everything and now you're increasing your calories, well, that's now a negative because you have to address the major problem of general energy toxicity. So I'm not someone who likes to demonize individual nutrients.

I just haven't seen really compelling evidence that seed oils are the root cause of the problems being suggested. And I think this is a good example that every time something comes up in the fitness industry, the opposite always comes up and it's the reactionary, extreme reaction to whatever happened here. And I think that's what we're seeing with some of the seed oils: It's mainly people trying to embrace the virtues of saturated fats. And listen, I think it's okay to consume some saturated fat. But again, I think limiting it to 7% to 10% of your daily calorie intake is probably wise, again, based on all the consensus of evidence that I've seen.

And once again, we are struggling with this. Well, we have this epidemiology and these mechanisms that sound good. But then what really happens when we do some randomized controlled trials in humans? And so far, I've simply seen no evidence to suggest that seed oils are bad for your health, regardless of the calories they contain. ANDREW HUBERMAN: You said the words "general energy toxicity." And I just want to highlight that I think it's a fabulous term. I don't think enough people think about that because they're prepared, or we're all prepared, to think, okay, seed oils could be bad.

Or artificial sweeteners could be bad. Or this particular component of the blood test could represent something good or bad, without taking into account the overall energy toxicity, the toxicity of excessive calorie and energy consumption. And thanks for pointing out that most of theData points to the fact that saturated fat should make up no more than 7% to 10% of total daily caloric intake. Is there a lower threshold that could be problematic? For example, I have noticed that my blood profiles, especially in terms of hormones, improve when I consume enough saturated fat. Maybe I'm a mutant. But years ago, as a product of growing up in the '90s, I tried a low-fat diet.

It certainly crushed my androgen levels. I started adding some butter again. And I was back in the sweet zone, where I wanted to be. So I'm guessing 7% to 10% of my total daily caloric intake probably comes from what I do now. I'll have to check it out. But is there any danger in reducing the level of saturated fat too much? LAYNE NORTON: Again, there are no solutions, just trade-offs, right? What maximizes testosterone may not be best for longevity and vice versa. I'm not making that claim specifically. But I think it's important to understand this: I think we all have the idea that there is one iconic diet that will be the best for building muscle, burning fat, and preventing cancer and heart disease.

And the reality is that there are generally healthy dietary patterns that we see are good for those things. But when we get into the weeds, there's probably some back-and-forth here, too. So when it comes to saturated fat, there is some evidence that if your level is too low, yes, you can have a reduction in testosterone. Now, is that reduction in testosterone, let's say 15%, 20%, whatever it is, enough to actually cause a loss of lean mass? That, we don't know. That has never been proven. Funnily enough, I just remembered this. There was a study that compared polyunsaturated fats to saturated fats.

And they equated total fat. And one of the really interesting things was that the group that received polyunsaturated fats had more lean mass at the end of the study compared to the group that received saturated fats. Now, it's just a study. I have never seen this replicated. This is a situation where I would like to know what the mechanism is because it could just be random. But if that's proven over and over again, what you might say is: Well, well, if polyunsaturates somehow increase lean mass compared to saturated fats, who cares what happens to testosterone? Unless that reduction in testosterone is causing some kind of impotence in your life, right?

All that to say, I really don't know. And by the way, that's something, for those watching and listening, real experts, every once in a while, you should hear them say the following words "I don't know." ANDREW HUBERMAN: Exactly. My graduate advisor was exceptional at that. And she was brilliant, right? LAYNE NORTON: And then in terms of cholesterol synthesis, you really need a very, very small amount of saturated fat for LDL cholesterol synthesis. Your liver can synthesize: The amount of LDL cholesterol or cholesterol that your body needs is very small in terms of living and being healthy.

So I don't think you should worry about that. And from a cardiovascular disease standpoint, there is some evidence that even taking people who have, quote, "low LDL" of 80 or 90 and lowering them to 30 or 40, there is still a benefit to the risk of cardiovascular disease. Again, you are weighing these two cubes. So what I'm saying is that if you eat 7% and 10% saturated fat, you're probably fine. ANDREW HUBERMAN: I've gotten a lot of questions about whether or not there are specific diet and exercise protocols for women. And I realize that this is a vast landscape. But some of those questions were related to menopause and premenopause.

And some related to the menstrual cycle. Most are related to variations throughout the menstrual cycle. In terms of, let's just say, diet maintenance or subcaloric diet, is there anything that you've observed? We'll talk a little bit later about this wonderful app that you produced, this Carbon app that helps people manage their energy consumption and a number of other things. And there you have a kind of database, or at least an experience base. And then I guess there are probably also studies that explore the differences between men and women in terms of adherence and what types of diets work.

Is there any general theme that can be drawn from that? LAYNE NORTON: This is going to be a really unpopular segment for women. It doesn't seem to make a big difference. ANDREW HUBERMAN: Well, actually, you might be relieved to hear that because it simplifies the classification of the information space and certainly the information that we've covered in this podcast so far. It means that not everything is different for them. LAYNE NORTON: Yeah, if you look at the relationship of studies of men versus women with diet, they seem to respond in a similar way. A similar calorie deficit appears to produce similar results.

Regardless of whether you're on a low- or high-carb diet, it seems to come down to the same principles. Now, regarding training, we know that in women muscle fibers adapt a little differently to training. But without going into too much detail, it doesn't really change how you should train because, for the most part, there are many different ways to build muscle. So we know that light loads up to 30 reps, as long as they are performed close to failure, have basically the same effect on building muscle, at least in the short term, as heavy loads with low reps.

It is mainly about bringing the muscle closer to fatigue or failure. It is not necessary to reach failure, but to get close, in a few repetitions. If you're between one rep and 30 reps, if you're getting close to failure, it seems to produce similar results. Again, great. You can choose the type of discomfort you prefer, right? When it comes to women-specific training, again, women actually, this is something that a lot of people don't know. In fact, they accumulated a similar amount of lean mass as a percentage of their starting lean mass as men. In fact, there is no statistically significant difference in the amount of lean mass they accumulate.

Now, the absolute amount of lean mass added will be greater for men because they started with a greater amount of lean mass. But the relative increase in lean mass is practically the same with similar training. Now, women, there are some differences in fiber types, women tend to be a little less fatigueable than men. They can go a little bit harder a little bit more. And there's also evidence that they recover a little better. But that could also simply be due to the fact that they can't use such heavy loads to induce hypertrophy. So I have this theory that while as a percentage of your one rep max, you can program things, I think absolute load matters.

When you look at elite weightlifters, the super heavyweights don't squat three or four times a week because they weigh 800 to 900 pounds. ANDREW HUBERMAN: They need to recover. LAYNE NORTON: I think there's a general recovery effect there. Again, I have no data to support this. This is just my observation. But when you get into the lighter weight classes (and this applies to men as well), you see quite a few people who do a lot of high RPE training sessions and seem to be able to recover from that. So I think the absolute load makes a difference. Now, when it comes to the menstrual cycle, this is one of those things where I tell people: do what you prefer.

So, there are some people who have said that you should schedule your training based on your menstrual cycle, that is, whenever you are going through your menstrual cycle, reduce the intensity. Reduce the volume because you won't feel as good. You're not going to train too. What I would say is just self-regulate that. If you come in and you're on your period but you're feeling good and doing well that day, then I don't think you necessarily need to back off. And there was a study that supported that notion. But if you come in and you're feeling terrible and you feel like you could use a reduction in intensity and volume, then it's totally fine to self-regulate.

And when I say self-regulation, self-regulation means that you are regulating the individual training session based on your performance. Then I will self-regulate to the extent that I am a super nerd. So I have a speed device. Then I can attach it to the bar and see how fast the load moves. And I know with different heating weights what speeds I should reach. So if I do my last warm up and my speed is about 10% higher than usual, I can be pretty confident that it will be a good day for me. If it's lower, I can back off a little bit.

In fact, at Worlds, when I did my last deadlift warmup, it was 30% faster than what I normally do in the gym. And I turned and looked at my coach and said, yeah, we're going to get this today. So there are several ways to self-regulate. But again, women, if you are on your period but feel fine, I don't think there is any reason you should back off. But if you're not feeling well, then it's totally appropriate to back off. ANDREW HUBERMAN: Raw foods versus cooked foods. People wanted to know if, for example, eating a raw apple versus...

I don't know. Does anyone cook apples? People used to bake...baked apples were a dessert when I was a kid. It was kind of a disappointing dessert. I'm sorry, Mom. That wasn't great unless you had a scoop of ice cream. LAYNE NORTON: Or apple pie. ANDREW HUBERMAN: And even then, maybe it's not great. But anyway, raw versus cooked. Obviously, if you burn a piece of meat to the point of turning it into pure charcoal, that's too much. And there is a small movement around the consumption of raw meats. That's not something I particularly enjoy. Frankly, sushi is the only raw food I personally eat.

LAYNE NORTON: Same thing. ANDREW HUBERMAN: And, frankly, I'm very careful about the source: reputable places. Is there anything real to this in terms of being able to extract the amino acids, vitamins and minerals from raw versus cooked foods? LAYNE NORTON: Looks great for Instagram. So when you cook foods, they actually tend to become... in terms of foods that contain protein, they tend to become more digestible, not less. Eggs are like that. Meats are like that. People say, well, when you heat proteins, you denature them. And I think they hear that word "denature" and think of destroy.

And that's not what denaturation means. So proteins fold into three-dimensional structures, you know, of course, based on their amino acid sequence. And there are specific energies of those amino acids. When you heat proteins or add acid, it starts to unfold that protein structure. That happens anyway during digestion. So I always chuckle when... I've seen some companies come up with "a way of cooking" that doesn't destroy amino acids. And I say, so you mean the normal way, right? So yes, in general, cooking actually makes amino acids more bioavailable, not less. Now, I would refrain from charring meat because there is evidence that charring creates polyaromatic hydrocarbons, which at least in animals, when given, appear to be carcinogenic.

So if you char the meat by accident, I would just cut off the charred portions. And then you should be fine. ANDREW HUBERMAN: Charcoal is delicious. LAYNE NORTON: ANDREW HUBERMAN: Not if it's too charred. But there's something about the charred crust of the meat. My dad is Argentine and he likes a good charred barbecue. LAYNE NORTON: Oh, yeah, yeah. ANDREW HUBERMAN: What's up? People referred to them in their questions as "carb blockers." But I think they are referring to things like berberine and some glucose scavengers. And one glucose buster that I would love for you to comment on is this claim that taking a brisk walk after a meal, or maybe even a slow walk after a meal, some movement can help reduce the amount of circulating glucose in some manner.

I've heard that. Not many people, but some are starting to pay attention to the idea of ​​taking things like berberine or even metformin that can eliminate glucose. I personally cannot take berberine. If I take it, I get huge headaches unless I've had tons of sugar and carbs. So I just don't get into it. But I know there are several people who want to know if these glucose scavengers can be useful or not. LAYNE NORTON: I think that's really majoring in the minors, if I'm honest. As far as carb blockers go, there's a little bit of white bean extract and that kind of stuff.

They block the digestion of carbohydrates, some. So when I say "block", to those watching or listening, the metabolism does not generally turn on and off. So when we say things like "lock," "dim," or "inhibit," we're usually not just referring to a switch on the wall that turns everything off when you press it. We're talking about a dimmer switch, okay? Then it just changes the emphasis. But these carb blockersThey can reduce the absorption of carbohydrates. Now, they don't seem to cause weight loss when done simply with a normal diet. Now why is that? Well, all it does is once those carbohydrates reach the large intestine and the bacteria take them up, they begin to ferment them into volatile fatty acids, which are reabsorbed in the liver.

Therefore, there is no increase in blood glucose. But you still get almost all the calories. It just has a different shape. ANDREW HUBERMAN: I see. LAYNE NORTON: So the carb blockers, they actually worked very well, I mean, if you block the absorption of something, your GI usually doesn't let the undigested material sit there. You have diarrhea. I mean, that would be the result. This is also how I debunked the full 30 grams of protein in a meal, you can't absorb more than that. I think if that were the case, when you ate a steak, you would start getting diarrhea every time you went over that 30 gram threshold, right?

ANDREW HUBERMAN: I remember during college, so this would be the early '90s, there was the Olestra trend. LAYNE NORTON: Oh, yeah. ANDREW HUBERMAN: This idea of ​​putting something indigestible in things like French fries so that they pass through the gastrointestinal tract faster and don't absorb as many calories. Obviously, this went nowhere. You don't hear about this anymore. But it does raise an interesting question related to energy balance, which is gastric emptying time. And, obviously, in the panorama of eating disorders, particularly anorexia. The use and abuse of laxatives is an unhealthy way that people try to control their weight.

And there are many problems with that approach. LAYNE NORTON: Oh, yeah. ANDREW HUBERMAN: But what about gastric emptying time? Is this a way people could control their energy balance in a healthy way? And where does fiber come into play? LAYNE NORTON: Fiber tends to improve gastrointestinal transit time because it adds bulk. So your gastrointestinal system is basically a tube. And it has peristalsis, which are wave-like contractions that move food down through the tube. Well, if the food has more volume, like with fiber, you can move it around a little better. Now, in the stomach, specifically the stomach, fiber tends to delay gastric emptying and slow it down a little bit, probably because it freezes a little bit.

Now this gets into the glycemic index argument, right? If you eat low GI foods, you will have a slower glucose release. It is a slower gastric emptying time. Does that affect energy balance? Therefore, there are quite a few studies comparing low GI foods versus high GI foods. In studies where calories are not controlled, low GI tends to outperform high GI. But when they control calories, it makes no difference. So what I think this suggests is that low GI foods, simply by their nature, tend to be higher in fibre. So I think it all comes back to fiber.

ANDREW HUBERMAN: Got it. I'd like to ask you for a moment about supplements. It is a huge landscape. But I think there are some things that you believe in, which means they exist. And there is decent data to support its use. Maybe even some anecdotal information based on your own experience, as long as we highlight it as such, could be interesting. I've heard you talk about two in particular, one that I'm very familiar with, which is creatine monohydrate. If you could share your thoughts on that, not just for building muscle but maybe for any other purpose.

And then the other one is one that, frankly, I'm learning more about all the time, thanks to your post, which is Rhodiola rosea (I think I pronounced it correctly) and why it might be interesting or useful to people. . LAYNE NORTON: Yes, as far as creatine goes, it's the most proven, safest and most effective support supplement that we have. I mean, there are now thousands of studies on creatine monohydrate. And I would also say very clearly that if you are using any other form of creatine, I think you are wasting your money. Creatine hydrochloride has some hype around it.

Apparently it is a little more soluble. The claim is that you need less. But there are only a couple of studies on it. And it's more expensive. ANDREW HUBERMAN: And creatine monohydrate is not particularly expensive. I realize that people have different budgets. But it's not a budget deal-breaker. LAYNE NORTON: Yes, it has become more expensive due to COVID and supply chain issues. There are forms of creatine that seem to be just as good, such as hydrochloride. But it's more expensive. And then things like creatine ethyl ester have been shown to be worse than creatine monohydrate. Buffered creatine is as good or worse.

And it is much more expensive. That's why I tell people to take creatine monohydrate. It's tried and true. It has been shown to saturate muscle cells 100% with phosphocreatine. And that's what you want. So, creatine works through a few different methodologies. One, by increasing phosphocreatine content, which helps improve exercise performance. It also appears to improve recovery. And it increases lean mass, much of which is due to bringing water to muscle cells. But I mean, muscle cells are mostly water. So when people say, well, it's just water, that's what muscle cells are mostly. And it also increases strength and some other metrics.

Now, it has also been shown in studies that people tend to have a decrease in body fat percentage. Now, that's probably because they're getting an increase in lean mass. And then what is relative is a decrease in body fat percentage. But there are some studies that also show a decrease in fat mass. I don't think creatine is a fat burner. I think people can train harder and build more lean tissue. And that's probably having an effect on fat mass. Then more recently, they've shown some cognitive benefits of creatine, which I think is really interesting as well.

But the only criticism of creatine that anyone has been able to find is because they have discredited what is related to the kidneys; they have discredited the study of the liver; There is no evidence that it damages healthy kidney or liver: it is hair loss. So what about hair loss? Because there was a study in 2009 that showed that creatine increased DHT. But they actually showed no effect on any other sex hormones. So it's a little strange. You would think that if there was an increase in DHT, there would be something else that would change as well.

And it's just a study. And again, it didn't directly measure hair loss. It measured DHT, which we know is involved in follicle loss. So what I would say is that I'm not convinced. It's just a study. It has never been replicated that I know of. And it was a mechanism rather than a result. So if you are someone prone to hair loss and want to avoid creatine because of that, I understand. But for most people, I don't think it's something to worry about. ANDREW HUBERMAN: Do you emphasize classic creatine loading, taking it several times a day and then reducing it?

Or just take it consistently at... I think 5 grams a day is the typical dosage that people take. LAYNE NORTON: Again, there are no solutions, only trade-offs. You can charge it. And you will saturate your phosphocreatine stores faster, usually within a week. If you only take 5 grams a day, it will take two, three or four weeks. But you will arrive at the same place. And you'll probably have a much lower risk of gastrointestinal problems. Creatine can be an intestinal irritant. If it is for some people, I would recommend breaking it up into several doses, so maybe several doses of 1 or 2 grams per day.

And definitely don't load it up if you're someone who has gastrointestinal issues. As for Rhodiola rosea, research is still in its infancy. I was reading a new systematic review that concluded that we need more high-quality research. But the research that does exist seems to suggest that it doesn't just reduce physical fatigue. But it also reduces the perception of fatigue and can also improve memory and cognition. And it is known as an adaptogen. So I really like it. My anecdotal experience is that when I combine it with caffeine, it tends to soften the effects of the caffeine.

It is a more pleasant experience. And there's also some evidence that if you're quitting caffeine, that can reduce the negative side effects of caffeine withdrawal, which, by the way, I didn't really believe in that until I actually went cold turkey, so Before a competition, I will eliminate caffeine for seven days because you can basically reset your caffeine tolerance in seven days. And two days later, I mean, I'm numb. I have headaches. I usually have body aches that arise because caffeine is actually a mild pain reliever. And yes, it was very interesting to see, but I slept like a baby, I assure you.

I slept like a baby. ANDREW HUBERMAN: And then you had caffeine before your event... LAYNE NORTON: To the meeting. ANDREW HUBERMAN: So you really want to get maximum impact. LAYNE NORTON: Yes. ANDREW HUBERMAN: That's why you do that. LAYNE NORTON: Yes. And like I said, Rhodiola tends to... not eliminate those negative effects. But it tends to make them a little moist. So I really like it. Again, I would like to see more research on this. But many more things are coming out. Ashwagandha is another thing that looks quite promising. It appears to modestly increase testosterone. ANDREW HUBERMAN: Interesting.

LAYNE NORTON: They've shown increases in lean mass. I don't think the increase in testosterone explains the increase in lean mass. It's just not a big enough increase. ANDREW HUBERMAN: Could it be the decrease in cortisol? People have talked about... LAYNE NORTON: It's possible. Decreases stress hormones. It has also been shown to help with sleep. But I would like to see more research that looks, mechanistically, at how it increases lean mass before conclusively saying this is the next creatine. More research is needed. And then there are other things that have an effect. Citrulline malate, there was a new meta-analysis that showed that citrulline malate can reduce fatigue and increase, I think, time to fatigue.

And in fact, it may have some small recovery benefits as well. In fact, different forms of carnitine may have recovery benefits. And actually... interesting... I think carnitine tartrate has been shown to... Volek published a study that showed that it increased the density of androgen receptors in muscle cells. ANDREW HUBERMAN: That's interesting. L-carnitine and its other forms are nice. I think there is good evidence that they can improve sperm and egg health in people looking to conceive. LAYNE NORTON: Oh, interesting. ANDREW HUBERMAN: Yes, there are a surprising number of studies on this in humans. But yes, the density of the androgen receptors, and that is due to oral L-carnitine.

People take capsules, they don't inject them directly into the muscle, yes. LAYNE NORTON: And then you have things like, obviously, the other most effective supplement out there is probably caffeine. I mean, if you look at the research studies, caffeine produces very consistent improvements in performance. So that's another one. Some people don't like the effect of caffeine. Alright. But... ANDREW HUBERMAN: I don't know because I've never gotten over it. LAYNE NORTON: Exactly, exactly. Well, interestingly, they show that the effect seems to be constant, that even if you are a regular caffeine user, you get a benefit every time you take it.

But like you said, you're used to it. So there are those things. Then you have things like beta alanine, which is found in our pre-workout. It's probably not very useful for most people in resistance training. It seems to have some benefits for high intensity. If you do more than 45 or 60 seconds of very hard training, it seems to help delay fatigue because of that. And then there are things like betaine, also called trimethylglycine, which there is evidence that can improve lean mass. There is some evidence that it can improve energy production. So there are some things out there.

But most things are not very good. So I think those types of supplements are very useful. But again, I would never tell people that they need supplements. Again, even something like creatine will have a very small effect compared to proper nutrition, recovery, and intense training. One of the things... I was talking to Ben Bruno the other day. And I said, you know, some people will ask me, how is this person progressing? Because his programming is not evidence-based? Or this guy, his exercises are stupid. And I will say yes, but they trained very hard for 20 years. One commonality seen among really successful athletes and bodybuilders is that they train very hard.

And one of the things I've observed is that the more they get into the weeds that people tend to get into (and again, this is just my own anecdote and observation) the moreThe more they get into the weeds, the less hard I see them train. . And one of the things that I really like is what Mike Israetel, who has a PhD and is a bodybuilder, said, that you can't beat hard training, that if you're looking to build muscle and you're looking to improve your body composition, the main thing is It is doing the work over time.

ANDREW HUBERMAN: Consistency and hard work. And I would add to that... and this also applies to academic endeavors, of course; I hope you agree... LAYNE NORTON: Absolutely. ANDREW HUBERMAN: --which is, yeah, the other thing is, given the mental side-- earlier we were talking about how satiety signals in the brain and what you think about food can be relevant. Learning to really enjoy training hard in addition to learning to really enjoy eating well, not just for the effects it has on body composition (those too, of course). But just learning to really enjoy the process of training hard and very hard training or very difficult work that you have to review or read a book that is challenging, learning to really enjoy it, I think, if there is a power. tool that exists, is the psychological end.

LAYNE NORTON: And I think a lot of that is gaining the confidence to do something difficult, that there's a reward in the end. I get asked a lot in my Q&As: How can I be more confident? How do I have more confidence? And I will tell people that you have to do it. There is no trick. You can't read about it. You have to enter the arena. And I don't necessarily mean competing in sports, but doing a PhD or doing something, just something difficult, that you're putting effort into. And you're saying, this is my goal.

And I'm going to do it. You learn a lot by doing that about yourself. And so, just what you said, I will reframe things in my mind when bad things happen... it doesn't mean I never get stressed, because I do. And it doesn't mean that I never get depressed, because I do, because I am a human being. But when something bad happens... I actually posted about this on my story today. When something bad happens I very rarely go anymore, poor me! Why has this happened to me? Because you are in the universe. Random bad things are going to happen.

So instead I say...if I'm not dead...instead I say, well, what an exciting opportunity to overcome an obstacle. And I bet, because in my life's experience, the most important lessons and the best things in my life have actually come from the most challenging and worst things that have happened. And again, I would never have been able to do this kind of thing if I hadn't done weightlifting, because weightlifting taught me a lot about perseverance, delaying gratification, and overcoming obstacles. And that's why I love him to this day. And I still get butterflies when I do a squat session, even though I've been doing it for 23 years.

ANDREW HUBERMAN: That's wonderful. Well, it's clear that you accept the difficult things. And for people listening to this, it obviously doesn't have to be weight lifting: picking hard things, learning an instrument, learning a language. The challenge is an absolute builder. LAYNE NORTON: And they've actually shown that kind of thing, when you challenge yourself and also mentally, I think there was a new study that basically shows a reduction in the risk of Alzheimer's and other age-related cognitive declines. I mean, basically, use it or lose it, right? ANDREW HUBERMAN: Yes, the desire and the will to persevere certainly translates into this thing we call the will to live, right?

It is related to the desire to live. Well, I think what you just said beautifully embodies what most people aspire to, which is... I think most people really want to do hard things. They don't just want to have the results. I think most people deep down understand that their reward system works that way. I must say that this conversation has been tremendously rewarding for me. First of all, it allowed me to meet you in person for the first time, which I really enjoyed. This certainly won't be our last interaction on this podcast and elsewhere. Plus, the amount of knowledge you contain inside you is amazing.

And... LAYNE NORTON: There's a lot of things going around up there. ANDREW HUBERMAN: And we all benefit because his ability to take advantage of the mechanistic side, again I think it's not limited but related to his expertise in biochemistry, right down to the impact on humans, animal studies, being able to understand where they are. those sit relative to each other. And obviously you are a practitioner. You practice what you preach. And what you're talking about refers to men, women, younger people, older people, vegan people, ketogenic people, carnivores. You can really generate a lot of ideas while still being nuanced and data-driven.

So I just want to say on behalf of myself and the listeners, I really appreciate you coming here today and sharing your knowledge with us. We will definitely point people to where they can learn more about you. And one of the places I definitely want to mention before we part ways is this Carbon app. And I should mention that this is not a paid promotion or anything like that. In fact, one of our podcast team members has been using Carbon for a long time. This is an app you created that allows people to navigate the space of exercise, nutrition, and energy balance to lose weight, gain muscle, lose fat, and maintain weight.

I'd just like to ask you briefly about that before we conclude. Without necessarily telling us everything there is in the Carbon app, I'd love to know what the main things it does and what it does. And then what were some of the key things that you wanted to make sure were there when you built it? What is the logical backbone behind this? Because I think there are a lot of apps out there for food counting, calorie counting, and exercise. Everyone I've talked to who uses Carbon, including our mutual friend Saagar Enjeti, this member of my podcast, etc., is raving about it.

So what is carbon? And what does it do? And what was your mentality when building it? What did you really want to see there that you didn't see anywhere else? LAYNE NORTON: Maybe your listeners don't know this, but I started coaching people online about nutrition in 2005. And that was the vast majority of my business until 2017. And I had a lot of success with that, whether it's just average people who looking to lose weight or build muscle and even elite level competitors in physical sports. So I had this idea, like... I don't want to say I had the idea.

Some people had the idea. What if we could take what I do in coaching and try to automate it as much as possible? Because when I was becoming a very popular trainer, it was expensive. You looked at me getting paid... I got to the point where I was getting paid about $1,000 a month for training. And most people can't afford it. And I would like to not only train rich people. You know what I mean? I would like to be able to help other people. So the idea was to create an application that could do some of these things.

Now there is always a place for human interaction. But for people who can't afford it, our app is basically $10 a month. And basically what we wanted to do was set up an app where... think about if you went to see a nutrition coach. What would they do? They will probably ask you some questions about your goals, take some anthropometric data, and perhaps dietary preferences. And they would use that information to formulate a baseline plan. That's what Carbon does. I think there are eight questions in the check-in flow about your activity, your exercise, your lifestyle, your body weight, your body fat percentage.

And if you don't know, we help you calculate it. Is not perfect. But it's better than nothing. And then your dietary preferences. And we use it to get to your baseline. And your benchmark will be your calories, protein, carbohydrates and fat. And what is different about our application? Because apps like MyFitnessPal or anything else will do that too. The difference with ours is that we encourage people to record their weight daily for the reasons we mentioned above. And then you can also track your food on the app. And honestly, I think our food tracker is much easier to use than most out there.

What we typically get rave reviews about is how easy our interface is, which makes intuitive sense. And to keep track of your diet, try to hit these prescribed macros. And each week, you'll be asked to check in with a trainer on the day you arrive. And then you put some information. And then depending on how you're progressing, the app will adjust or not adjust depending on how you're progressing. So, for example, if you're hitting a weight loss plateau, it will detect it. And it will reduce your calories. Or if you're trying to gain weight and have plateaued, you'll increase your calories.

And there are many back-end algorithms that take care of this. But the crux of the app is that we're trying to determine your total daily energy expenditure because that's going to tell us the first thing we need to know, which is, how many calories do you need to eat to reach your goal, right? So at first we basically make our best guess based on their anthropometry. It's not going to be perfect. But it will take us to the stadium. And if you know, as some people already know, well, I know what I keep my body weight at, there's actually a place where you can enter it manually during the registration flow.

That's helpful for people who are super nerdy like me. But then people will ask, well, do you take data from the Apple Watch? Do you take this? Do you take that? And no, for the reasons we mentioned, it overestimates energy expenditure. What our app does is an algebra equation. If you... Because of your body weight, your maintenance calories are your total daily energy expenditure. The average number of calories you consume to maintain your body weight will be the same as your total daily energy expenditure. So if we know how body weight changes and we know how many calories the person consumes, we can calculate what the energy expenditure is.

And you can see in the app that... there's a maintenance calorie tracker or an energy expenditure tracker. And usually, after about three or four weeks, even if the app was off at the beginning, you'll be pretty close because, let's say, someone shows up. And your goal is to lose half a kilo a week or something like that. And the first week they lose 3 pounds. Now, the app actually takes into account the fact that you can lose more water weight the first week. Then they probably wouldn't get an adjustment. But let's say next week they lose 3 pounds.

The app will detect that and adjust your calories because it will estimate that your energy expenditures are actually higher than you previously estimated based on the amount of weight you are losing. And the same thing happens in reverse. If they are not losing the amount of weight they are supposed to lose, you will reduce them based on the fact that they may have overestimated their energy expenditure. But that's the first crucial point: tracking that energy expenditure. And then the next thing is protein. So when the back-end algorithm happens, the calories are first set based on your energy expenditure and your goal.

So, for example, if you're on an aggressive diet, your calories will be lower even if your energy expenditure may be a little high, simply because if you're trying to lose 2 pounds a week, I mean, we'll be in a pretty aggressive calorie deficit. So first you will set the calories. Then, you'll set protein based on your lean body mass. The leftover calories will then be allocated to carbohydrates and fats based on your dietary preference. And we have some different dietary preferences. The balanced diet is approximately 50/50 to 60/40 carbohydrates and fat of the remaining calories. Then you have low fat, which is obviously a higher proportion of carbohydrates.

You have low carbs. You're on a ketogenic diet, which is very, very low in carbohydrates. And there is also a plant-based option. And within each of those options, still, you can go in and change the macros a little bit within a certain range so that you can dial in what your specific dietary preference is because, again, if we go back to what it is to produce the best results. In the long term, it is what the person can accomplish. So we really tried to start with the concept of adherence by allowing people to have whatever dietary preference they want.

And there are other applications that are good. For example, we get asked a lot, what is the difference between our app and the Renaissance Periodization app? And they have a great application. But his is a little more rigid. And he will say: you are going to eat so many meals. And you are going to consume these foods right now. So we are the complete opposite. We want to give you maximum flexibility. Now, some people would prefer the rigid structure at first. But we found that, for most people, giving them more flexibility generally improves long-term adherence. This is how it worksapplication.

And again, there are multiple different goals. It is not just a weight loss app. There is maintenance. There is muscle development. So there are all kinds of different goals that can be accommodated, different rates of each of those goals. And I mean, I've used the app for over three years to measure my body weight. And I mean, when I say that it has marked me, because I am very regimented when it comes to recording and logging my weight. So what I set out to weigh at the World Cup I lowered to 0.1 kilograms. ANDREW HUBERMAN: That's fantastic.

LAYNE NORTON: It was great to be able to use a tool I helped develop to train myself. So it's a great tool. We did some statistics. We surveyed 2,500 members. And one of the questions we asked ourselves is: would you recommend this to a friend? And 91% said yes. So I think our average retention is seven months, which for an app that costs $10 a month is really great. ANDREW HUBERMAN: That's great. Yes, as I mentioned, several people I know use it. This is not a paid promotion. But I think people need guidance and tools. And what we know about the human brain is that improvising can work, but the brain often tricks itself.

There's a quote from Feynman about this. And I will do it wrong. It's always bad to try to quote Feynman because he said it so much better. But we are the easiest... basically it's easy to fool ourselves, is what he was saying... the easiest to fool ourselves. LAYNE NORTON: Absolutely. ANDREW HUBERMAN: Sounds great. We will put a link so people can see it. Again, it sounds like a wonderful tool and a tool that brings together many of the principles that are important issues for weight loss and gain. I guess what most people are looking for is targeted gain in lean tissue and maintenance of weight, because a number of people would like to just maintain it.

Listen, I really appreciate your time and everything that you're doing, certainly, your time, energy and knowledge today, but also what you're doing on the various social media channels. And the very fact that someone coming from the depths of academia is sharing so much knowledge in so many domains means that you are a gem in this nutrition landscape and a person that people really need to hear from. Thanks for your time. LAYNE NORTON: Thank you. I appreciate the opportunity. I really enjoyed it. ANDREW HUBERMAN: We'll do it again. Thank you for joining me today for my conversation with Dr.

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