Debunking the paleo diet | Christina Warinner | TEDxOU

Translated by: Rik Delaet Reviewed by: Feike Laffeber Thank you, I'm glad to be here. I am an archaeologist who studies the health and

diet

ary history of ancient people through bone biochemistry and ancient DNA. I'm going to talk about the

paleo

diet

. It is one of the fastest growing fad diets in America. We could live longer and be healthier if we abandoned our modern agricultural diet. That would make us sick. We need to go back to eating like our Paleolithic ancestors more than 10,000 years ago. I'm really interested in this idea because it aims to harness archaeological knowledge to use data from the past to help us today.

Beginning in the 1970s with the book “The Stone Age Diet,” it has since diversified into several variants, including the Paleo Diet, the First Blueprint Diet, the New Evolution Diet, and the Neanderthin Diet. The jargon for these diets refers to anthropology, nutritional science, and evolutionary medicine. The diet seems aimed primarily at men. The ads show virile, caveman figures, slogans like "live primitively" and "lots of red meat." The idea behind this is contained in four parts. One: current agricultural diets are making us chronically ill, they do not adapt to our biology. Second, we must abandon these agricultural diets and go back in time, to the Paleolithic, to eat more like our ancestors over 10,000 years ago.

Three: we know what these diets were like and that they were based mainly on meat, supplemented with vegetables, fruits, some nuts and oils, but certainly no cereals, legumes or dairy products. Fourth: If we start to imitate this ancient diet, our health will improve and we will live longer. I want to make it clear today that this version of the

paleo

diet promoted in books, on television, on self-help websites, and in most press releases is not based on archaeological reality. That was it. Thank you! (audience laughter) No, I'm not going to end here. I'm going to explain.

As an archaeologist, I'm going to demystify some of the basic archaeological concepts on which all of this is based. Then I want to talk about what we really know from the archaeological record and scientific studies about what Paleolithic people ate. Myth 1 is that humans evolved to eat meat and that Paleolithic people ate large amounts of meat. Humans have no known anatomical, physiological, or genetic adaptations to eating meat. On the contrary, we are much more adapted to eating plants. Take vitamin C as an example. Carnivores produce their own vitamin C, because it is found in plants. If you don't eat plants, you have to produce them yourself.

We can't produce it, we have to get it from plants. Our digestive tract is longer than that of carnivores. Because our food stays in our body longer, we have more time to digest plants. We need more intestinal surface and more bacteria. We have omnivorous teeth, molars so large that they are used to crush the fibrous tissue of plants. We don't have snapping molars, which are the specialized teeth carnivores use to break down meat, and we have some genetic mutations adapted to the animal diets of some populations, but for milk, not meat. These arose during agricultural periods in certain populations, mainly in Europe and Africa.

I call it 'The Meat Myth'. The idea behind this is that we should eat a lot of red meat, but that's simply not true. The meat in this dish comes from fattened cattle, that is, from domesticated animals. The food of Paleolithic people was probably very lean and small in size. They really wouldn't have eaten much meat. Bone marrow and organ meat would also have been very important. We see evidence of this in animal remains that still show the characteristic cutting of bones to extract the marrow. Certainly people ate meat, especially in the Arctic and in areas with long periods without plants available, they ate a lot of meat.

But for people who lived in more temperate or tropical areas, a large part of their diet was vegetables. Where does this meat myth come from? From two sources. One is rooted in the nature of the archaeological record. 80% of bone mass is mineral. This will preserve much better for thousands of years than delicate plant remains. But there are also earlier biochemical studies on bones that were done on Neanderthals and early humans. The biochemical study of bone is based on the analysis of stable nitrogen isotopes. It's complicated, but I'm going to explain it simply. The basic idea is that you are what you eat.

There are heavy and light versions of nitrogen: N15 and N14. We get it through our food. But there is an important difference. The higher you are in the food hierarchy, the more N15 you consume. By measuring the amount of N15 in the bone, one can deduce where that organism is in the food chain. This is an example of a generalized isotope model. Plants are usually at the bottom, with herbivores on top and carnivores on top. But not all ecosystems listen to this model. There is a lot of regional variability. If you don't take this into account, you may reach erroneous conclusions.

Let me give some examples. We see some very strange patterns in ancient animals and humans in East Africa. First of all, how can a man be taller than a lion? Lions only eat animals. So why is he above the lion? It turns out that the foods you eat are not the only ones responsible for these isotopic values. Drought can also play a role. Here we will probably see a difference in access to water. Let's move from the savannah to the tropics. For example, with the ancient Mayans. Once again we see something different. The ancient Mayans are on par with jaguars.

We now know that the ancient Mayans ate a lot of corn. What's going on here ? We don't know exactly, but we believe this is due to their way of growing and fertilizing crops. Let's now move on to the Pleistocene. Here we also find a series of interesting patterns. The reindeer stay very low, even in the plant area. We see wolves where one would expect to see herbivores, and we see mammoths spread across the three levels, along with plants, herbivores, and carnivores. We suspect that in very cold climates animals eat unusual things. In this case we think that mammoths eat lichens and bark, which makes their values ​​seem very strange.

If we look at people today and in the past, we find them in the same isotopic space as wolves and hyenas. But if the regional isotopic ecology is misinterpreted, the wrong conclusion can be reached. I think it's too early to say that this is solid evidence for meat consumption. Because we still know very little about Paleolithic ecosystems. Myth 2 is that Paleolithic people did not eat whole grains or legumes. We find stone tools from at least 30,000 years ago, that is, 20,000 years before the invention of agriculture. People used stone tools like mortars to grind seeds and grains. More recently we developed techniques to examine "tartar." Very interesting: it is fossilized dental plaque.

We can isolate dental plaque from people's mouths and extract plant microfossils and other remains. My team develops methods to extract DNA and proteins, while other research groups focus on microfossils such as starch grains, pollen and phytoliths. We're still in the early stages, but even with the limited research we have, there are abundant plant remains in the tartar of Paleolithic humans. Including cereals such as barley. We find barley in Neanderthal teeth or dental plaque. We also find legumes and tubers. Myth 3: Paleo diet foods are what our Paleolithic ancestors ate. That is simply not true. Any food depicted in these advertisements is domesticated food, agricultural products.

They come from the transitional phase of the Neolithic. Let's take an example: bananas. Bananas are the agricultural food par excellence. They can no longer reproduce in the wild. We have "eliminated" their ability to produce seeds. Every banana you ate is a genetic clone of every other banana, grown from cuttings. Make sure she is housebroken. A wild banana is so full of seeds that many people here wouldn't even recognize them as edible. Salad seems like a great food for the paleo diet. Except it's completely tailored to our needs. Wild lettuce contains a lot of latex. It does not digest and irritates our gastrointestinal system.

It is bitter, the leaves are hard. We domesticate it to obtain softer and larger leaves, to eliminate latex and bitterness, we remove the thorns from the leaves and stems of wild species to make them tastier. The tomato shown here lacks the toxins tomatine and solanine of its wild relatives, all members of the poisonous nightshade family. It is true that olive oil is the only natural vegetable oil that can be harvested without synthetic chemicals. But it takes at least rudimentary pressure to get it out. Nobody in the Paleolithic could make them. This is domesticated food. I found this model diet on a website.

It sounds like a delicious and nutritious breakfast, but no one from the Paleolithic ever sunk their teeth into it. Blueberries come from New England, avocados from Mexico, and eggs from China. (Laughter) This was never on a Paleolithic plate. And finally, we have a size problem. Cultivated blueberries are twice the size of wild ones. We already talked about bananas. Now avocados. A wild avocado may have a few millimeters of flesh, and the same goes for wild olives. And of course, chickens are exuberant producers. They lay an egg almost every day. Predictable, large and in abundance. But the same is not true of wild chickens, they do not lay all year round, they are not so easy to find and the eggs are usually small.

If you're still not convinced, let me give you a few more examples. Everyone knows it as broccoli. Broccoli didn't even exist in the Paleolithic. On the left you see wild broccoli; it looks very different. But wild broccoli is also wild cabbage, wild cauliflower, wild kale, wild kohlrabi, and wild Brussels sprouts. They all come from the same species. The only difference is that they are different cultivars. We have selectively bred the same species to produce the type of food we like best. These are human inventions. Broccoli is interesting because it is something strange. What is broccoli? It's such a strange looking vegetable. (Laughter) In case you don't know, they are the flowers of the plant.

We turn the wild plant into something that produces so many dense flowers. It produces something strange, but they are flowers. If you don't believe me, buy some broccoli, put it in a vase like the one on the right and it will bloom. You will receive a beautiful bouquet. (Laughs) Now let's talk about carrots. You'll recognize the carrots on the right, but on the left you'll see the wild carrot. Contains falcarindiol and natural pesticides. They taste bitter and taste bad. But we have refined them, we have made them bigger, much bigger, much sweeter and with many more vitamins, because that is what we want.

Many of you don't know that almonds and apricots are closely related varieties of plums. But almonds no longer contain cyanide, so we can eat the seeds. With the apricots we went for larger, thicker fruits, because that's exactly what we wanted from that variety. They are very closely related and, like carrots and broccoli, are essentially of human origin. Now let's talk about real paleo diets. First of all, I must clarify that there is not only one type; There are many paleo diets. As humans roamed the world, they ate local foods, which of course were highly variable. When we talk about paleo diets, we have to speak in plural.

Let's look at an example. We go back in time 7,000 years to Oaxaca, Mexico. You're looking at the view outside the Guila Naquitz rock shelter, one of the first sites in Mexico. This is a photo I took in December. People lived there then, and here you can see what they ate. This has little to do with a paleo diet or what you would find in a supermarket. But there was plenty to eat here in the right season. September was Guila Naquitz's time. Then, many people would gather at these shelters and eat the local food. As you can see, that consisted of a lot of fruit, legumes, agave, with which we make tequila today.

Also all kinds of nuts, beans and pumpkins. And a lot of game, especially rabbits. But in April there were few foodstuffs in this region. So they moved to other places with more food. So we might ask what we can really learn about the world's Paleo diets. We can make some general observations. One: that they are regionally variable. People above the Arctic Circle must, and will, eat something different than what people in the tropics eat. Their food sources differ. People in places without plants will eat more animals, and people in places with lots of plants will eat more plants.

They are seasonal, becausePlants produce food at different times. Herds migrate and fish spawn according to the seasons. As a result, people have to move constantly, with great periodic mobility, sometimes over long distances. Again depending on the region. The food packages used to be small. If you harvest wild broccoli, you will have to harvest a lot to have as much as the modern variety. The foods he found were generally hard, woody and fibrous. They would eat meat, but also bone marrow and viscera. The animals would generally be very thin. Eventually the food would be eaten. Plants still contain varying levels of toxic substances.

But also phytochemicals, including very healthy ones. But this type of diet is almost unviable today. Three billion people on this planet cannot eat like foragers, there are too many of us for that. Can we learn lessons from these paleo diets that we can still apply to our lives today? And the answer is yes'. I think there are three important things: First, there is no right diet. Diversity is key. Depending on where you live you can eat very different things, but you need diversity. We cannot synthesize many vital nutrients on our own, including vitamins. We have to get it from our food.

Eating a diet rich in species is very important. Unfortunately, in today's American diets the trend is going in the opposite direction. When you buy processed foods at the store, it doesn't matter if it's cake batter, mayonnaise, or coffee creamer, increasingly you'll find only three types in almost everything we eat. That's corn, soybeans and wheat. That's going in the wrong direction. Secondly, we have evolved to eat fresh foods, when they are ripe. So it has the highest nutritional value. But we also have to talk about storage and preservatives, because in large urban societies you can't always eat everything fresh.

The food goes bad. Some foods, such as seeds and nuts, store well naturally. That is why they were so important to agricultural people. But we can preserve them in another way, by salting, sugar and vinegar. We can pickle them, smoke them, dry them and add artificial preservatives. The interesting thing is that they all work the same way. They inhibit the growth of bacteria. But remember that our stomach and intestines are also full of bacteria, good bacteria that do you a lot of good: they digest food, regulate the immune system and promote the functioning of the mucous membranes.

If you eat foods full of preservatives, how does that affect your microbiome, your good bacteria? And the answer is, "We really don't know." We are just starting to investigate. Third, we have evolved to eat foods in their natural covering, fibers, shell and all. It turns out that this is really important. Your foods are not just the sum of calories and vitamins. The indigestible parts are also important. The fiber you consume regulates the speed at which food passes through your intestines. They modulate the metabolism, slow down the release of sugars, have all kinds of functions, feeding the good bacteria in your intestines.

We are increasingly seeing that low-fiber foods are associated with microbial communities that cause things like obesity and diabetes. Unfortunately, in the globalized processed food system, we lose these compounds, we lose whole foods. We eat reconstituted and concentrated foods. We lose the benefits of fiber and pectin from fruit juice because they have been filtered. We all lose this balance. As an example of how all of this has become so unbalanced, we can now eat many more calories, much more food in a very small package without even realizing it. That short-circuits the ability to know when we've had enough.

I have a question. Imagine drinking a current regular size soda (950 ml). You go back to the Paleolithic and want to consume the equivalent amount of sugar. How much sugar cane, if you found a cane field, how much cane should you eat, how many meters of cane should you eat? I have some sugar cane here. How many meters of sugar cane do you have to eat to reach that level? Someone knows? 1...how many bars should you eat? They are quite big. No, not 12 meters. You would have to eat 2.5 meters of sugar cane to reach that level. That's a lot of sugar.

There's no way anyone from the Paleolithic era would have eaten that much sugar cane, even if they really wanted to, and you can ingest it in about 20 minutes. By disconnecting whole foods from the nutrients they contain, we trick our bodies and can override the mechanisms that have evolved to detect fullness and satiety. These are the three most important lessons we can learn from Paleolithic diets: There is no one right diet, but dietary diversity is important. We should eat as much fresh food as possible and we should eat it in its entirety. Anthropology and evolutionary medicine can teach us a lot about ourselves, and new technologies open new windows into the past.

But we still have a lot to learn from our Paleolithic and Neolithic ancestors. Thank you. (Applause)