World's BIGGEST intermittent fasting study - what we learned | Prof. Tim Spector & Gin Stephens

What is the

biggest

misconception you hear about intimacy and

fasting

? People think that you are starving yourself or that it is difficult or that you are going to be hungry or hungry. Hi, I'm JY Stevens. JY Stevens is an

intermittent

fasting

advocate and

intermittent

presenter. Fasting Stories podcast, she is the author of 28-day fast start, day by day and the New York Times bestseller Fast Feast, she repeats instead of thinking: can I eat? Yes, I think I'm giving my body some time to rest. I've rested my gut microbes or have some downtime the first time I tried intimate intermittent fasting I absolutely hated it you and I are pretty different you're always thinking about your next meal right you got this where are my snacks?

Now I feel judged, Tim and how long would it last? It will take you to get Jonathan into shape. I think it would take you two weeks. I think you'll be surprised at where your body prefers. What seems natural to you. What's sustainable is

what

's healthy because that's

what

matters if you don't do it. You don't enjoy doing it, you're not going to do it, just that little thing you might think, how could that make a difference? Absolutely welcome to Zoe Science and Nutrition, where

world

-leading scientists explain how their research can improve your health, Jin. and Tim, thank you so much for joining me today, so we have a tradition, Jin, that you may remember, where we always start with a quick round of questions that come from our listeners, both ready to do it, yes or ask, it starts with Tim ago The latest science suggests that intermittent fasting can improve my health.

Yes, can intermittent fasting improve my energy levels and mood? Yes, if I fast for most of the day, can I eat whatever I want the rest of the time? No, unfortunately, it's not right. Jen, most people. get used to intermittent fasting within 28 days um yeah I'm the only one who finds intermittent fasting very difficult no but I can help you with that we will definitely continue with that okay and finally you can have a complete sentence. I enjoy food less if I fast regularly. No, you will enjoy it more. Okay, we had a lot of questions about it.

Yes, as someone who runs a company that does a lot of data science, this is something that fascinates me. YouTube has been telling me that 69.3% of you. Those who watch this channel frequently haven't hit the subscribe button yet, so I want to ask you a quick favor: choosing to subscribe helps us a lot, helps us give the show better access to the

world

's leading experts, and ultimately, to make further progress in our mission. to improve the health of millions, so if you enjoy this show, all I ask is that you hit the Subscribe button and in return I promise that we will continue to make this show better and better every week.

Jen, it's great to have you back on the show. and the last time we recorded you you were in the middle of a hurricane doing this remotely and we were waiting for the roof to fall and the internet to go out, so I think hopefully now that we're in person, we should be safe, but the Another thing that's even more exciting than having you in person is that we have a world exclusive, so since our last recording, Tim and our incredible team of Zoe scientists led by Sarah Barry have completed what is actually the largest

study

of the world on intermittent fasting That's really exciting with over 100,000 participants, it's like a really big

study

and so I'm really excited to discuss some of our initial findings, which would be the first time we've talked about this, you know, in this kind of big event. scale in a public setting and I'm also really looking forward to discussing this because I participated in the study myself and it was the first time I tried intermittent fasting and transparently I absolutely hated it, Jin, so I went with it.

I did the required weeks. and I couldn't wait for the day I stopped. I was so happy before I started that I'd like to start from the beginning with you, Jen. Okay, what is intimate about fasting? The words sound so scary to you. The word fasting makes you think. you're going to like 40 days and 40 nights wandering in the desert but intermittent fasting the word intermittent is key you're having fasting periods and eating periods that every person listening or watching already does that's just changing the balance of that you know you go to bed you sleep you wake up in a fasted state probably everyone listening has had fasting blood tests before, so our bodies are already fasting every day if you live an intermittent fasting lifestyle , the difference is that you just extend that period instead of most people having so much for their eating time and so much for fasting, we just change it and so you're fasting for a longer period of the day intentionally and I know there have been many different types of intimacy. ism fasting and a lot of evolution I think about science and see what is best, we just explain at a high level what they are and then talk about what is in fact.

I think today it seems to be the area that people are most interested in, both from a scientific point of view. and also in terms of just being able to do it and finding that they have a good experience with it, well, all of intermittent fasting is any kind of approach where you can have periods where you're intentionally fasting in balance with food and energy. most. common or what most people think of when they think of intermittent fasting is also known as time restricted feeding or if you really want to do the research in the lab with rats you could call it restricted feeding Tim, but those are daily meals . window approach where every day you can eat within an 8 hour window or a 6 hour window or whatever eating window works for you and it doesn't have to be the same day to day.

There is another completely different branch of intermittent fasting under that umbrella which is alternative daily fasting people in the UK probably heard of it in the past under the name 52 back in 2012 that was a great approach 52 43 but most of people who practice intermittent fasting as a lifestyle tend to gravitate towards time restricted eating the daily eating window approach, that's what I do and the 52 wasn't really a proper fast either because it allowed you to have like 500 calories or something like that, so I think we're talking about something completely different here and the 52 just disappeared. Anyway, the fad people realized that it wasn't as good as it was designed to be, so I think people are gravitating towards this way of eating which, as we said, is not so much fasting but simply changing meal times. , exactly yes, we want to.

Focus on that, if they called it intermittent, eating something like that wouldn't be so scary, but like, oh, fasting, oh, it doesn't scare Jonathan, so we have to convince him that it's not something we can do. We've had a few episodes talking about circadian rhythm. with several really great scientists recently and I think that's definitely part of what seems to have influenced this and this is obviously a 24 hour cycle so focus a lot on this idea, there's a time of day when you have to do things . and a time of day when you shouldn't and it seems like that plays a lot into this idea of ​​thinking about eating at particular times of the day in a sort of regular 24-hour rhythm.

Well, I'd just like to point out that "You all know from your research with Zoe that bioindividuality is an important component of what you're doing, it's everything you're doing and I think that applies to circadian rhythm as well. You know I work with fasters." blinkers from everywhere". In the world who live intermittent fasting as a lifestyle, you know I've worked with hundreds of thousands of members of my communities over the years and you figure out what works for you over time, there are people who tend to have a window to eat earlier or a midday eating window, but most of us tend to gravitate towards the afternoon and evening just as a practical way to live our lives, but we are not all the same.

That said, there is that variation, but I think what you're getting at is. the fact that all humans have a circadian rhythm, which means that your body has to do active things at a certain time and then rest at another time and all of us are prepared for that, so it has become clear that this diet must be done at the same time. At the same time your body is in activity mode and not complete rest mode, and I think this has also been linked to the cadian rhythms of our gut microbes having to deal with the foods you eat if it's at odd times. and this also applies to the idea that shift workers and people who do things that are out of sync have poorer health because of that, so I think we're increasingly realizing that we have to get back to our ways. origins and this means eating. at times when we would normally be active rather than very late at night, particularly exactly, but everyone realizes that over time you discover where your body prefers what feels natural to you, although advertisers would love that we ate sandwiches all night in front. from television, that's true, you know, they can make a

prof

it, it's not for the benefit of our bodies and our health, so that's brilliant, so having explained this idea, it's like you're in this rhythm of 24 hours and you said talking. about reducing the time when you do this this EA Tim I actually think it's a brilliant time to talk about this new study, you know, the world's largest study on intermittent fasting called the big study yeah, could you tell us first place about the study what happened and then what we found, yeah, the big thing, if it's not a question mark, is whether this is intermittent fasting and it came out of a big health study that we were doing in the UK called the health study Zoe and there were two To 146,000 people who were sort of eligible for this, we told them what it entailed, which was just monitoring what they eat for a week so we could document what the normal eating periods were and then the idea was to eat within a feeding period of 10 hours for 14 hours. of overnight fasting and 10 hours of feeding, which is not very strict, but has been shown to be effective in a variety of animals and humans. 37,000 of them completed the study and how long did they have to do it?

They fasted because they did it for two weeks, 27,000 were very committed and continued for many more weeks, after that some of them up to about 16 weeks and a proportion were still going so we know we have people hooked on Baseline . It's a shame that their eating period was about 11 hours, so for many people they only changed it by about 1 hour. People who completed it lost on average about 1.1 kilograms, or a little more than a couple of pounds in weight, but most importantly, we saw that people you know reduced that eating window. Most changed more and we saw increases in energy levels of 22%.

Mood improved by 11% and hunger, which most people thought would have increased, actually decreased slightly, so hold on. I just want to make sure I understand what you're saying that for the people who did this, even though they were eating in a shorter time than before, they were actually less hungry than before they restricted their eating, that's what they were reporting, so that sounds like this. Counterintuitive, very counterintuitive, when we looked at people who didn't do this consistently, so they had one day to do it another day, we didn't discover that actually things were the other way around, those people were hungrier and had less energy, so that clearly. you need some kind of stability to get these benefits and we also saw that the people who benefited the most had an eating window that was larger at the beginning, those people who maybe ate during the 14 hour window benefited the most from this and the people I knew were marginally close to that when they started, so the other thing we found is that people actually had some intestinal symptoms that improved, so the bloating went down by 11%, which was interesting because you know there have been some links between people with gut problems maybe some doctors would say we undereat and often that's good for you but we actually found that the opposite of snacking was also reduced in people so almost everyone said they were snacking less, which is pretty obvious in a way, but it's good. to document that there was actually one less snack on average per person.

We also saw differences in time-restricted early eaters versus time-restricted late eaters and this is something that JY knows a lot about all the studies that suggest that metabolically early is a little bit better for you if you saystop eating at 6:00 p.m. instead of 9:00 p.m. and consequently snacked less, but interestingly, when we looked at our data on who completed the study, more people chose to eat time-restricted late rather than early, meaning they continue eating into the evening, but they start to catch on. so late starters could start eating at 11:00 11:00 and go until 9 p.m. In that example, instead of starting at 7 and continuing in the UK, that was a more popular option than the other one that you know could end, you know, at 8:00 in the morning until 6:00 p.m. at night, so there was a 2/3 to 1/3 split, which I think is really interesting because it suggests that what we're looking for here is how to get people to change their habits long term. that is sustainable, so they should choose one that suits them, so there is no point in telling everyone that they must do this at these particular hours, otherwise there is exactly no value in getting people to choose their own regime it seems be effective and that's really what we saw so there were 37,000 people who completed this out of 148,000 who signed up so clearly some people didn't like the idea once they were forced a little bit like you Jonathan if you had Had the option, you say well, maybe I skipped that. one, but what we're seeing is about a third of the people who weren't chosen for their interest in nutrition can do this quite effectively and benefit from it and I think that's the real message that people who hear this know that there's a good chance they're in that group and you know we should all experiment ourselves and try it yeah I think what it really is is you let them choose when they wanted to do it and they naturally chose what felt right to them and that's What we find in our community is the majority of people. you end up having the window that changes a little later you wake up in the morning you are already fasting you know think about the history of food and foods and what we call things you know that a snack awakens your appetite the first time you eat in the day which sparks your appetite, so if you're just late when you open the window, it's a lot easier to keep fasting than to stop during the day and close that window when you're used to snacking, you know from me.

I usually stop eating around 7:00 p.m. Every day is when I've had enough, you know, I'm not tempted to eat because I'm not hungry anymore between 7:00 p.m. and bedtime now, if you told me that I had to have an early eating window and that I had to open at 8 in the morning and then stop, I would be hungry again before going to bed and that wouldn't be a very pleasant lifestyle while I'm sleeping during that part. where I would be hungrier I wake up and I'm fine, it's been a shock to me because I was definitely raised with this assumption that you have to have breakfast, it's very important before you leave and I think also Another misconception that we were raised with is that you have you have to have food inside you before undertaking any activity; otherwise, you know whether it's walking to school, going for a jog or riding a bike, you've got to have carbs up there, you know. prepare for it and now we know that's not true yeah and we did a fascinating podcast looking at this just for men at this stage and we're looking forward to seeing the data also for women looking at exercising fasted or not and In fact, this The surprising fact that doing some exercise quickly could be beneficial for your health is one of the things that has made me more and more intrigued by this idea that it's not just crazy to do all my exercise on an empty stomach, yes, I also.

And I think actually a lot of people now get out of bed and the best way to exercise is to not think about it and just do it, and then once you've done that you might start thinking about food, but say. It's very different from maybe even 10 years ago when you knew that science was a doctor and we were told that you have to have reservations before you can do this activity, otherwise everything will fail, so I think everything has been turned upside down. and this is this. That's why you know we need to look at how these kinds of lifestyle changes fit into our culture and what we're doing and how we work.

In a way, O gave us this overview of the results and I know these are the preliminary results, what about this for you? It is surprising that something new has been discovered. Well, looking at the literature, I mean, a lot of the things about this have been done in mice and clearly it works very well in mice, but not in humans. mice, we don't eat like them, we don't sleep like them, and you know, if you combine most of the studies to date, they've been done in small numbers, usually young men, 600 participants total, it hasn't really been that way. broad, so I think it was the first time we did a pragmatic study of people to see how many found it easy and how many found it difficult, because the key part of this is not only does it work if you do it, but also how easy is.

It's doing it long term as a lifestyle and I think this type of community science study is doing something very different: it tests the sharp science for a few weeks but also gives us a real sense of how easy it is to continue. and I think the other surprising results that other people at Haven saw are things like energy, mood, and hunger, because there was a lot of fixation around this around weight loss and cardiovascular health, like the heart, and things like that, not there because it's very hard to ask a mouse, I guess what its mood is or how much energy it feels like it has, so these things feel very different from that, right?

You could actually feel a different energy in a couple of weeks, it seems like you already know that. just a normal person who seems to be completely different from anything that has to do with their heart health or their weight, so for me, just looking at these results crudely, I see minor changes in things like weight, you see small changes in metabolism and insulin and things like that, but the one thing I really took away from other literature that I don't think people have highlighted is that you're getting a steady reduction in inflammation, now inflammation is this activation of the immune system and that's what The only thing that stood out from all the studies is that, on average, inflammation is reduced by giving your gut a rest and gut microbes are improved and this has this effect throughout our body and that's why it's important to energy and mood and our immune system in general, and you know that small amounts of weight loss are a side effect for some people, they are not the main reason to do this modest time-restricted diet because it is very modest, you know we're just Changing many people just one or two hours a day isn't a big difference compared to these trials that have often combined this with calorie restriction.

This study was pretty short-term, so it was two weeks and I think one of the things we talk about all the time at Zoe is like you know the only thing that really matters is long-term sustained change in your life. , so this is clearly like proof of something, since scientists often do the right thing, in the short term. then learn about something long term, so if people had stuck to this shorter eating window based on all the other science out there, what health benefits they could expect and you mentioned something about inflammation, could you help us? to understand that and in other places, what would that really mean?

Which means you hear some of them say: I want to do this as a permanent change in my life. If we see this reduction in inflammation and assume that this will continue, there is no reason to think otherwise, then you would see small changes over a wide area. of health, that means that your immune system is working better, that you are reacting better, that your gut microbes are in a better state, that they are producing better chemicals, it means that your mood will improve, you will have less depression, less anxiety. You'll feel more energy overall, less fitness, and maybe have some small changes in your response to sugars.

Minor changes to your fat levels, which will reduce your risk of heart disease, etc., so it won't suddenly change your risk. A few weeks from being from high risk to low risk is not like the silver bullet that cures all ills and you will live another decade of healthy life just because of the restricted time eating absolutely not, but if you multiply that small difference in the inflammation for years, right, that's what it adds up to, which is what we want people to do. There is no point in doing this for 3 weeks and then stopping. No, you have to find something that suits you and then do it for a long time.

Realize how. It's important to give your gut and your body a break, and if you can just prune it, you know that there are low levels of inflammation that are going to have huge effects on your risk of pretty much every disease, because we know that aging-related diseases are cancers and all these others. There are things related to this initial level of inflammation that you know through our poor lifestyle and you know that the Western diet has made it worse, so I think you are seeing a small change over really long periods of time that will bring these benefits and maybe Some people will notice that they know these energy and mood levels more than others, so every time we talk about study, we talk about averages, yes, and that means you know some people will see more, some people will see a little less.

Do you remember when you first talked about this? I thought it sounds completely crazy, like I've never heard of this and this was after Zo started, this was maybe four or five years ago or something JY was already doing with her. time-restricted food, but that was the first time and at that point there was some of the first data that I know you said that started coming out. I think it's really all mice to start with or 20 students or something sitting here in 2024 now and you Describe this big study that we do with Zoe, but there are a lot of other smaller scale studies that you know of, different studies from different time periods, like how strong is the evidence around that improvement in the type of inflammation that you're describing and, more generally, like where are you?

Feel pretty safe, where are you saying? Hey, look, this is exciting, but the research is still early and we're still going to learn more to have more confidence. Well, we will definitely learn more. We definitely need long-term studies that follow people. to see what happened to them and look at their blood, you know, years after they started this, which doesn't exist, so right now we're connecting a lot of the dots, from mouse studies to SP human trials to Greater Community studies , uh like the big study yes, but if you take everything together, you basically see nothing harmful in this for the vast majority of people, you know some rare little exceptions and a huge potential for benefit that we can't express at this moment how great they are.

The benefits will be, but I would certainly say to anyone who knows that my level of content is good that you will get some benefit, whether small or large, I think that remains to be seen, or over time it will probably depend on your starting point, at same as We saw in this that if you are someone who snacks all the time, as many government guidelines tell you, let's be honest, you are eating all the time and you do this and you end up eating up to 10 uh. window or less, you're likely to see some pretty big changes.

I'm about to move on to JY and talk about how we do this in a really practical way, but just before we do that, Tim, what does that mean to you personally? I tend to start. eating at 10:30 or 11 in the morning if I'm doing any exercise or training or whatever I do in the morning I'm not hungry when I wake up on my own unless I'm jet lagged so right now everything B they're out, I'm pretty jet lagged and then I'd finish eating or drinking anything other than black tea or black coffee at 9:00 at night and I do that probably six, five or six days a week. absolutely rigid because I realize that I want to sustain this for the long term and I don't want to feel like a failure if I've given it.

I know this because I've definitely seen you drink a glass of wine after 9 o'clock. with me to know that you are and you're not, which is one of the things that I love, like you're always like you don't have to be perfect to get moderation. In moderation it is so I think you have to do it. I realize you want to do this as a long-term goal and we know that if you can do things five days out of seven, you're doing pretty well, but every once in a while you know I can be in France and there's an amazing buffet breakfast and I say, I'm really going to miss everythingwhich they did, but it was fascinating.

They painted the oral cavity of these small rodents with artificial sweeteners, it's as if they had a mouth, they painted their mouths with it, they didn't even swallow it, they just tasted it and they had a sealed phase insulin response, which means that the pancreas of the little rats released some insulin in response to So, in the second part of the study, which was not so human, they cut the nerves from the tongue to the brain, they repeated it, the rats could no longer taste it because those nerves were cut , they didn't have the insulin response of the calico phase, so it was the taste that made the difference and what does insulin do?

Does insulin lower blood sugar? Why does your body release insulin in response to these sweet tastes or these food flavors? Because our brain knows that sweetness comes from honey or fruit or whatever our body makes. I don't understand that they think you're going to eat a raspberry, even if it's just raspberry tea, that's not exactly the case, so your brain says we know fruit is loaded with sugar, we're going to need some insulin to handle that. and then your pancreas releases insulin, only if you've had zero calories, then it could lower your blood sugar and make you feel shaky and worse than if you hadn't, so that's what your body might think you're doing.

If you're hungry, then you're starving because your blood sugar has plummeted and, you know, if you're using a CGM, you could actually see it as a drop in blood sugar after having that insulin response in the calico phase that returns to some how to think about this. day to day, yes, it cleans very quickly after hours. I'm deciding to eat. What else do you need to know to make this transition? Is there anything else you need? Just cleanse quickly and get on your way to what makes you feel good. We don't expect you to lose weight in the first month because your body is learning to do something new, sometimes people find it because you're not metabolically flexible but you're not adapted to the Fats, we call it, you're not.

You really make good use of your fat stores because your body hasn't had to do that for a long time. If you eat like most people eat, you may initially overeat in your eating window because you're not well-nourished during your period. quick, your body can't really tap into stored fat, so you open the window and think, "I'm starving" and then you just overeat, that goes away once your body flips the metabolic switch, so don't worry so if you feel like you're done, this is never going to work. I open the window and eventually eat too much, I definitely feel like I don't know if that's common.

I feel like I had some anxiety because Tim laughed, but he had some anxiety as he approached the end of the window. They say he may not have eaten enough food. You may not survive the night. It's not that I won't survive, it's that I might be hungry and that will affect how I do. Feel good here's Norm, I don't worry if I still want to eat more food I can get more food okay you don't have to eat for future hunger that's the nice thing you just close the window you're not eating for future hunger you go to bed Actually , eating later at night will make you hungrier sooner than if you had stopped earlier, so I better eat a lot because tomorrow morning I'm going to be fasting.

In fact, tomorrow morning it will be more difficult than if you had a counter. Inur, yes, and how long would it take you to get Jonathan in shape? Well, if now he's going to clean up quickly and not have the Earl Grey, I think you'll be surprised, so how long do you think it would take me to change? from saying this it's very difficult to saying I'm starting to get all those mood energy benefits two weeks yeah I'm drinking hot water in a cup right now just hot water just wake up and drink that or you're used to a little caffeine in the morning, you could have some black tea.

I'll stick with my black coffee. I bet you could do it right away. Well, I think you're challenging me. Go. I'm willing to give it two weeks. I can't last a whole month. I'm willing to give it another two weeks of clean fasting. Try waiting until 11: See if you can wait until 11: and imagine knowing that your body is doing all these wonderful things that really help. to think about can I still eat? Can I still eat? You know, looking at your watch. I think I'm giving my body some time to rest a bit. Do I have germs or am I having downtime?

I have always found when I fast longer. the busier it was, the easier it was AB, so I would never suggest anyone to start on a weekend, because that's the worst time, yes you stay busy, how is that your experience? Oh, absolutely correct if you have time to sit and mope. about it, that's when you say, well, I have nothing to do, sure I would like to eat a muffin, but if you're busy you don't even think about it, yeah, and what about the time that goes by, Tim, what is it? the there is evidence because and I know this is an area that is still subject to a lot of discussion, but for example, I probably eat 14 hours a day, not every day, but there are definitely a lot of days where I eat 14 hours.

I understand from quite a few scientists I've been talking to that it's probably not ideal, but on the other hand I think you're definitely not sitting here saying that people should eat all their food in four hours, we don't have enough large studies in a group that wide enough with people and not enough women in particular in our studies, although you know we were lucky in most of the studies where the women were women, but it seems like that's the sweet spot for when the results start. becoming significant occurs in this 10 hour eating window so if you can get to 10 hours that's fine there is some evidence that maybe 11 hours that you know might be fine and there are probably differences between people so here we are talking about averages that can vary at different ages and between men and women we still don't really know those differences, so for the moment I think it's doing something that is sustainable, so if you can have a 10 hour feeding period that seems to be sustainable for years because that's what our ancestors did, that's nice. easy, but for some people they might want you to cut it down to 8 hours, others might be fine at 11: and to flip it the other way, my feeling from you and sarah bar et al is like more than 12, you seem to be saying I'm really skeptical that that's a good thing for you, right, right.

I think it's all right to suggest that there's a linear relationship between how long you can do it and in terms of the biological benefits, but at least at the same time, it becomes harder to do it for most people, so it's just a tradeoff of where these two lines go. That means you're pushing that if someone could eat all their food in an hour, it would be no. We're not going to not recommend that day to day, we know we know that people who only eat one meal a day struggle to get enough calories, vitamins or nutrients, so for the vast majority of people that is detrimental and for many athletes . and things have tried and it fails miserably.

We don't want to have a really short, short, tight feeding period. Now, how you really define short and tight depends on the person you know. I'm someone I've been doing this for. For many years I have had a feeding window of about 5 hours, which is my sweet spot, which works very well for me. I can nourish my body well. I can maintain my weight so I think really the key is what are someone's goals are you not trying to lose weight you don't need to lose weight it wouldn't be good for you to lose weight but if someone had a lot of fat to lose they have to give it time your body to burn more fat so that's when you might find a shorter eating window, but there's still no one hour eating window every day, it's definitely not something we recommend, so a 10 hour eating interval and then the question is whether you should do it early or late, and the evidence says it's good if it's easy for you. do it early, but if like me you know it doesn't fit with your life etc and you go out in the evenings and socialize then it's best not to try to force it on average, maybe it's better to start early. but in reality, it is the most important thing, but as we say with everything, what is sustainable is what is healthy and that is why two thirds of the people in the large study chose the window to eat late, since they know that it is easier for them go ahead. with your life, so I think there's always this difference between theory, what happens to mice or paid students in a lab, and what happens in the real world, and this is what we're finding out, what are really people? you're not going to do it because that's what matters if you can't do it and you don't enjoy doing it, you're not exactly going to do it and if you went on vacation to Italy or Spain and you know you wouldn't do it If you couldn't eat at night, you wouldn't find a restaurant, so I think there has to be some flexibility around culture and work practices and where you are in the world and your family and all these other considerations, but I think we're giving people a model to which they can adapt this science to their own lifestyles.

Can I go back to one of the questions at the beginning because we got this from several listeners who basically said, you know if I follow this very strictly can I eat whatever I want? Can I eat whatever I want? The answer is yes, but also no, and it's really in the emphasis, you know, if you think about eating whatever you want, that implies that you're going crazy and just eating everything that won't work very well for your health, won't work. very good if you lose weight, but you can eat whatever you want, that is, if you are someone who does better.

Learn more whole food plant-based approach, you absolutely can do it with intermittent fasting. If you are currently following the Standard American Diet and have not yet changed your diet, you can implement intermittent fasting and continue eating what you are eating right now knowing that you are getting positive benefits, but then a funny thing will happen. Most people who start eating whatever they want on the Standard American Diet eventually lose their taste for it and discover that what they want is different. now your mind certainly did when I started in 2014. I was eating the standard American diet.

He was obese. I was 80 pounds heavier than I am now. I liked that fast food that I like to take out now. I don't want to eat that way and it has happened naturally, my body has directed me towards more nutritious foods, so you feel that the long periods without eating have helped you, so to speak, to fight some, perhaps these ultra-processed foods ​And these other things, I'm just like that. What you're suggesting is a very common thing we see in our intermittent fasting community, people suddenly say, "hey, I tried my favorite coffee creamer that I used to enjoy and now you know they're drinking black coffee while fasting, but they ate it." during their feeding period and they said and it tasted like poison.

I don't like it anymore. We lose the taste for things we used to enjoy. It's pretty much something that happens almost universally over time. I don't have to worry about calories, I think that's the kind of thing because if you're doing this intermittent fasting, that means you're free and you can have unlimited calories, no, no, that's the answer, you know Donuts are not the one. correct answer nor the reward for this, but it just means that you still have to eat the same way, it's a healthy plant-based way, Zoe style, we don't count calories at all because we know that in the long run it's not a good solution. but you still care about the quality of the food, it's a complement to the Quality, but suddenly it doesn't like to override it at all and like JY says, you know that if you take a little break, maybe you'll feel the quality of it more. your food. that what you've done before by getting to know black teas and coffees, you're maybe introducing more bitterness into your taste systems, your brain, and naturally you'll slightly reduce that need for sugar and things like that.

You're right. Really Think that by drinking black coffee or simple tea, our taste buds change over time, they regenerate. You have new taste buds in a few weeks, so if you train your palate to enjoy black coffee, enjoy black tea. Suddenly you feel like, oh a. Brussels sprouts are delicious because you tolerate those bitter flavor

prof

iles of the greens. One of our previous guests we had recently was Professor Karen Esser, whose focus on the circadian rhythm, particularly within the muscles, she was concerned about for people over 70. They may not be able to eatenough nor getting enough protein within a restricted period by Tim despite being pretty positive about this sort of thing in general.

I think it's something you think about but for most people it's not a problem, I think if you're both trying to lose weight and are exercising a lot then having too dramatic a change could be problematic in that small group. , but I think what we're talking about here are pretty modest changes, you know, changing your feeding window from, say, 12 hours to 10 hours isn't really going to affect anyone. I think only if you're dropping dramatically that would have an effect because you wouldn't be able to get enough calories or protein during the day at that eating time and that's maybe what he was referring to is these more extreme extremes of these fasting periods, but What we're talking about here, which are very modest changes that would last for years, people would be getting all the nutrition that I think they need and a What we find over and over again in the intermittent fasting community is that we become very better at listening to our bodies, you know, we've built in hunger and satiety cues that drive our eating and protein is an example, you know, I eat a lot of plants these days and um, but every once in a while I feel like I really need a little meat today, my body tells me if I eat too much meat I start to feel sluggish, so I don't worry about knowing when I'm eating enough. protein because I really feel like my body is letting me know that you know people aren't really satisfied until they've eaten enough and your body will tell you.

I think that's absolutely fine, as long as we're sensible about it. a wide variety of foods from which we do not exclude large areas of food and we do not try to fit into a small window and at the same time lose a lot of weight, so I do not see this as a problem. we have a lot of protein in plants and other things as long as we have that variety and you know we're not so limited that we don't have enough time to eat everything we need and I wanted to add that you know working your muscles is important as you get older , so I've become much more intentional when it comes to working my muscles because use them or lose them correctly, eat protein, eat enough within your window, but you also have to be active.

Now I am an older person. You know, you're old, very old, you definitely don't look old, but you know, I'm 60 years old and you know, I've practiced this for years and I've certainly only seen benefits, so I don't see my muscles fading, so it sounds. As you say, be pragmatic in particular cases where people may be trying to lose weight or you see them losing weight. Yes, obviously there is common sense, but in general again because you're not talking about very narrow windows where it's kind of impossible to do this it's not you and your body worried about my book that I wrote in 2020 it's called Fast Feast repeat it's not fast eat some diet food repeat you know we want to nourish our body well I think it's a beautiful place to um To stop this time, let me try to summarize and I know you'll both keep me honest.

We started out saying something like what is intermittent fasting and today, in 2024, that's mostly this idea, this other term for kind of restricted eating by Tim. is saying I'm only going to eat for a certain number of hours each day and generally it's going to be pretty much the same cycle every day and then there's a discussion about how long, which could be, you know, as long as such time. 12 hours in some case up to, you know, 6 to 8 or something like that on the other end and Tim, I think you said there's really nothing harmful for most people and great potential for benefits, so it's something that we should not fear and, in the same way, it is not going to solve everything, but it is something very exciting.

Then share the results of this new study, the big study we did. in Zoe with 148,000 people participating, which was a 10-hour eating period, which from Jyn's perspective is still a relatively long period, meaning that 14 hours without eating was over two weeks and what you saw was that There was a small amount of weight loss equal to 2 pounds, 1.1 kilograms, which you said is a minor change. What was most exciting is that you saw these improvements in energy and mood and decreased hunger in just two weeks in this very large real-life sample. and that, interestingly, it worked particularly well when they were consistent in their patterns, people were more inconsistent, they actually ended up hungrier or with less energy, and then there were people like me who are just miserable like that and who, practically speaking again , you saw that people tended to actually tend to eat later in the day is a little at odds with some of the guidelines around health.

The reason we think this might be working is we think this is reducing inflammation in the body because it's not forced to work at times when we're evolved, you know you don't have to deal with all this stress from the foods and that this small change in inflammation over time can really add up so it can really affect your health, from your immune system to then it affects every part of your body, so it could really add up and improve. You know how long you have quality of life. JY. I think you talked about pretty much what it means critically if you think about it.

In that regard, it's like you have to accept that there is a transition period, so you can't just change tomorrow and find it easy, so I was probably expecting something too easy because you need to move to what you described as metabolically flexible, which means being able. Just do your normal things with your reserves rather than without food, as generally people find it easier to continue their fast in the morning, so if you're trying this transition it's much easier to say that instead of having breakfast at night. 7:30. I'll change it later, secondly, you have to be very strict with what you do outside the window to eat, so cleaning quickly is what you said so I can have black coffee, black tea, but I'm not even allowed. like my Earl Gray or my herbal tea or things like that, keep all of that in your eating window, you can have hot water, you can have coffee, but that's basically it, don't worry too much, if at first you overeat during the fasting period, it will balance. and then also recognize that, although it is not a magic solution, you cannot like to eat unlimited calories during the feeding period and expect not to magically gain weight, you have to continue to think carefully about the quality of the food, as if ultimately this does not was going to work. to make up for the fact that you need to eat foods that you actually know are healthy for you instead of, oh, okay, I can go eat my Donuts because I only eat four hours a day and then, maybe to finish it off, we talk about ordering . of the eating window and I think my conclusion and Tim corrects me on this mistake is that more than 12 hours is not good, which is actually similar to the advice that Satchin Panda gave on the podcast recently.

Really short, not good either, so you're None of you are believers that one meal a day is the secret of the house. Can I talk to HP about the idea of ​​one meal a day? I vaguely think of myself as one meal a day, but more than 5 hours I think about it. like a multi-course meal laid out like it has an appetizer and maybe a plate of salad, so it's a feast, it's a feast, right, but we're not talking about an hour, an hour, no, no, I got it and So I think Tim said his sense of timing is a sweet spot for both health and sustainability is about 10 hours, but still the data is pretty early and could vary between people, so This is very average and we don't know it yet. for different ages and men and women and people with different conditions, but that is the current state of the evidence that we have and I can only tell you anecdotally that it absolutely varies from person to person, we are each a study of one when it comes to finding out what What works best for you doesn't exist, that's how everyone should do it for intermittent fasting, yeah, so you know don't beat yourself up if you can't get exactly that, if you need an extra hour and that works for you. absolutely fine, I think it's about listening to your body and this is really what we're trying to get people to do is not not listen to Dogma, listen to your body, love it, I think that's a wonderful place to stop.

Thank you very much to both. I hope you

learned

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