Instant Genius - What our evolutionary history can teach us about eating well

Episode Date: September 24, 2026

These days, supermarket shelves are filled with thousands of different products all vying for our attention; the options are almost endless. However, if we look back in time, we find that our early ancestors simply ate what they were able to hunt and gather and eventually farm. Thanks to the huge number of options we now have available, many of us choose to follow diet plans of various kinds, be it veganism, low-fat, low-carb, or the paleo diet, but what can we learn from evolutionary history about what we should really be eating if we want to live longer, healthier lives? In this episode we’re joined by Prof Daniel Lieberman, an author and evolutionary biologist based at Harvard University, to talk about his latest book, Fed Up – What Evolution Reveals about Food, Diet and Eating Well. He tells us why many of us find it so difficult to eliminate certain foodstuffs from our diets over the long-term, how humans evolved to store more body fat than other mammals, and why the good news is that humans are perhaps nature’s ultimate omnivores. Take your curiosity further with a subscription to BBC Science Focus magazine. Every issue is packed with fascinating insights into the science behind everyday life, the latest breakthroughs and expert analysis, delivered straight to your door. Receive an extra £5 when you subscribe using the code SF5OFF, (minimum spend £20, see full terms and conditions on our website). https://www.ourmediashop.com/bbc-science-focus-magazine-pod30 Learn more about your ad choices. Visit podcastchoices.com/adchoices

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Hello and welcome to Instant Genius, a bite-sized master class in podcast form. Every Monday and Friday, you'll hear world-leading scientists and experts talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor, a BBC science focus. These days, supermarket shelves are filled with thousands of different products, all vying for our attention. The options are almost endless. However, if we look back in time, we find that our early ancestors

simply ate what they were able to hunt and gather and eventually farm. But thanks to the huge number of options we now have available, many of us choose to follow diet plans of various kinds, be it veganism, low fat, low carb, or the paleo diet. But what can we learn from evolutionary history about what we should really be eating if we want to live longer, healthier lives? In this episode, we're joined by Professor Daniel Lieberman,

an evolutionary biologist based at Harvard University, to talk about his latest book, Fed up, what evolution reveals about food, diet, and eating well. He tells us why many of us find it so difficult to eliminate certain foodstuffs from our diets, how humans evolve to store more body fat than other mammals, and why the good news is that humans are perhaps nature's ultimate omnivores. So welcome to the podcast. Thanks so much for joining us. Oh, I'm delighted to be here. Thank you.

So in today's episode, we're talking about your latest book, Fed Up, What Evolution Reveals About Food, Diet, and Eating Well. So let's sort of kick off talking about the eating well bit. So these days, more and more of us are interested in eating a healthy diet. But there's so much information and advice out there, and often quite a lot of it is conflicting and it can be quite confusing. So what's the sort of the overriding thesis of this book? I begin with the very simple observation, which is that we never evolved to choose our food.

For millions and millions and millions of generations, our ancestors were just happy to eat whatever it is they hunted or gathered. And then, you know, after the origins of farming, people were, you know, just ate what they grew. And now we have this very strange, modern world in which you walk into a typical supermarket. In the United States, there are about 40,000 products in a typical supermarket. In the UK, it's maybe about 30,000 your supermarkets are little smaller than ours, but still, trying to choose from among 30,000, 40,000 products in which many of them are manufactured to be appealing and convenient, but they're also very unhealthy, is a challenge. And then at the same time, not only are we confronted with this incredible abundance of food,

much of it ultra-processed, but we're also confronted by this incredible cacophony of dietary very advice. Some people say you should never eat saturated fats. Some say butter is just fine for you. Some people say never eat seed oils. Some people tell us to do on Tuesday, mushrooms are bad for you. On Wednesday, mushrooms are good for you. You know, go be low carb, low fat. And people are really confused. And I teach the stuff, right? And I'm confused. So I thought if I'm confused, it's time to write a book. So let's sort of briefly go back in time to early humans before we get up to the modern day. So, you know, what do we know about what they ate? they ate everything. That's the whole point. I mean, humans evolved in Africa, but Africa is very

diverse and in different parts of Africa. You know, some, some there are their deserts, their highlands, their forests, et cetera. There's incredible diversity of foods that our ancestors ate in Africa. And then when we dispersed out of Africa, that diversity of foods even increased. So our ancestors ate anything they possibly could that moved or grew and wasn't poisonous, which they could, which they could use to fulfill the basic goal of life. which is to eat food and have babies. So we didn't evolve to eat food to be healthy. We ate food in order to maximize a reproductive success.

There was no one paleo diet. There were dozens, hundreds of paleo diets. Yeah, so that's quite interesting, because that's sort of one of the common diet programs that people follow these days. And you think, well, it's called the paleo diet, you know, from the outside, that must make sense. But as you just said there,

It's more of a kind of triumph of branding over actual research. Well, you said it, not me, but I think that's true. I mean, look, there are some sense, all of these diets, even the craziest diets, have a grain of truth, right? And the paleo diet, you know, there's some sensible things about it. It's a high protein diet, you know, maybe you don't need as much protein as they say, but, you know, it's not a bad thing. And it tells us not to eat, you know, sugary foods and processed foods and foods laden with saturated fat. That's all good. But it also completely forbids, like a lot of diets, there's elimination.

It completely forbids us to eat any legumes. So no beans, no lentils, no chickpeas. None of these foods that most of us think are healthy, including peanut butter, which is my favorite food. And it also bans all grains, all cereals, even whole wheat grains and cereals, which most experts, me included, think are very healthy. And that's based on some false notion that our ancestors never ate these foods, which is untrue. and the false notion that somehow these foods have anti-nutrients that bind to minerals and vitamins and cause us to be malnourished. And it is true that uncooked, unfermented grains and beans do

do cause those problems. But if you cook them, you remove these compounds to harmless or non-existent levels, and they're healthy. They're not bad for us. So when did, you know, early humans actually start cooking food? What do we know about that? Ooh, good question. I mean, if I knew the answer, I would write a paper instantly for nature. There's a bit of a debate. I mean, we know that by a million years ago, there are some, we see evidence for some fires

in the archaeological record, and there might be some that are older, but it's really about three to 400,000 years ago that fire becomes a really big thing. In England, there's a site that's from like 300,000 years old where you can actually see the traces of them actually making the fire, you know, the flints that they were striking

to kick the sparks. So starting around 300,000 years ago, fire and cooking became a regular part of our diet. It was so important that we're now actually adapted to eating cooked food. It's very hard to survive on a raw food diet. Because cooking increases the amount of nutrients we get from food. It makes foods healthier and safer. So our intestines got smaller.

I mean, our biology changed. So trying to survive on a raw food diet is really hard, very hard. It's challenging. Yeah, so I was going to ask that, because you actually know from personal experience, don't you, about attempting a raw food diet? I don't think you're a fan. Yeah. So for the book, I thought I tried to pair various diets with the history of diets. So I started off the raw food diet and a paleo diet went after that and all that. And without a question, the raw food diet was the hardest. I mean, I just couldn't, I just couldn't get enough energy,

despite spending a ridiculous amount of time trying to, you know, make salads and smoothies and this is and thatses and whatever. It was just, yeah, I just couldn't. I just couldn't get enough energy. I just, just after a few days, my wife quit before me. She quit after three days and I quit after four days. It was just unsupportable. So let's move on to what we're actually eating then. So you talked there about different sort of legumes and different plants, etc. But these days, a lot of us still do eat, you know, quite a lot of meat. So when did we start eating that? And, you know, what effect did that have on us? Well, origins of meat eating. was really important in our evolution. It probably started sometime between three and two million

years ago. It's hard to be precise. But by two million years ago, we were hunting animals. In fact, that's one of the reasons I got interested in all this because I studied how we hunted through by running animals down. That was work that I did a while ago. And meat for the, you know, your typical hunt together is a lot of variation. But, you know, maybe in Africa, about 30% of the diet came from meat in most tribes. But remember, we ate meat not because it was health. per se, for long longevity, but rather because meat is really nutritious and delicious and played a really important role in our evolutionary history. And now, of course, some people think, well, you know, we should only eat meat. And of course, there are others, you know, it's interesting,

there are carnivore dieters who believe they should never let a plant pass their lips and vegans who never allow meat to pass their lips, which I think is fascinating. It shows us just how incredibly omnivorous we are. Humans can just survive on almost any kind of of diet. So just because our ancestors ate something or didn't eat something doesn't necessarily mean it's good or bad for us. So let's stick with me then. So these days a lot of people's, you know, if somebody goes to the doctors or the cardiologist or something or if they're, you know, they're a bit overweight or something, they'll ask them about eating, you know, do you eat me particularly red meat? You know, how much red meat are you in? You know, as you said there, we've been eating this for millions

of years. You know, is it really that? bad? Let's just put it this way. Meat is very nutritious. I mean, meat has all the, pretty much almost all the nutrients you need. It's full of protein. Of course, it's very low in carbohydrates. Meat can have, depending upon the cut of meat, it can have a fair amount of fat. And so, yeah, meat is very nutritious, no question about it. But meat also, like all foods, all foods, and meat is no exception, have tradeoffs. And it turns out there is evidence that the more people eat meat, especially red meat, the higher their risk of a range of disease. In fact, you can do what's called a dose response study. If you increase, you eat 84 grams of

meat, it increases your risk of dying after correcting for age by about 13%, which is interesting. And if you double that, you more or less double the risk. So meat is nutritious, but it also seems to be slightly promote, especially red meat, can promote cancer. It's associated with heart disease. I mean, in general, animal foods, despite their incredible importance in human evolution, are not associated with good health as plant foods. That's shown in study after study, after study, after study. Now, that doesn't mean you shouldn't eat animals. It just means that, you know, we all have to make up our minds about what we're going to eat and what tradeoffs we're going to have, but there are no simple answers to essentially what is, you know, quote unquote, an optimal

diet. There is no such thing as an optimal diet. So let's have a look at you, you mentioned earlier, this idea of elimination diets, which a lot of people, most commonly when they're trying to lose weight or even to be a little bit healthier, I'll say, well, you know, I'm going to try cutting out carbs, let's say carbs. So we go on a low carb diet, like things like the Atkins diet. So what's the theory there? Well, the theory is really scientifically very sound. So when we eat carbohydrates, sugar being the most, you know, one kind of carbohydrate or white, flour or brown flour, which is a less refined carbohydrate, that carbohydrate has glucose in it. And glucose is a kind of sugar. And when glucose gets into our bloodstream, we can only handle a

very small amount. In fact, in your entire bloodstream, you have about five liters of blood in your body at the moment. And you have about one and a half teaspoons of sugar in your blood right now, just one and a half. And if you even go slightly above that or slightly below that, your brain figures that out and reacts because we want to keep that concentration. very precise. So when our blood sugar levels go up, insulin, which is the hormone that deals with this, goes up quickly. And insulin's job is to get sugar out of your bloodstream into your fat cells. You store it as fat. Insulin also tells our fat cells to hold on to that fat and not break it down and turn it back into energy. And so high carb diets can promote weight gain. There's no question

about it. And low carb diets are good for preventing weight gain or losing weight. The problem is that, again, everything has tradeoffs, right? And one of them is that I like carbs. Most people like carbs. I tried the Atkins diet, and it's really hard. I mean, I like, you know, my muslin for breakfast, and I like having a piece of toast every once in a while. And, you know, going to a really low-carb diet is very unsustainable for a lot of people.

So it turns out that low-carb diets do help people lose weight a little bit faster than other kinds of diets. But that's the efficacy, the real, you know, the ideal. ideal effect of the diet, but the effectiveness, the real world consequences are that many people struggle to keep up with these diets and then they add carbs back into their lifestyle because we like carbs and carbs are useful and if you're a runner like I am, carbs are really important. So that's the theory behind it. And the other thing is that when you don't eat something, you usually replace it with something else. And one of the problems with these high fat diets is that, low-carb diets is that they can be very high fat and high animal fat diets,

and that increases a risk of heart disease. So we have to be careful about how we do these diets. From morning hockey with a cup of coffee to timbits and road trips, Tims and Canadian Tire have always gone together. Now it's official. You can now earn Canadian Tire money at Tim's. Link your Triangle Rewards and Tim's Rewards accounts to earn twice with every Tim's run, terms and conditions apply. Visit timhordens.ca.ca. Slagal for details. Another approach in diet, which is really popular, so I sort of grew up in the 80s,

and it was really popular, was that everyone was going on the low-fat diet. Because, I mean, it seems quite plausible, isn't it? I'm carrying a bit of extra fat. Maybe if I eat less fat, then I will lose fat. In that logic, it sort of makes sense, but what's actually going on? Yeah, well, wouldn't it be nice if we're that simple? But unfortunately, nothing is simple in nutrition and ingestion. And look, fat has twice the energy density of carbs and protein.

So that's one logic behind it. So if you lower your fat levels, right, you should be eating fewer calories. So that was one reason. And then the other logic behind low-fat diets, which, by the way, I was raised with. My mother feared fat like, you know, It was like poison, right, as far as she was concerned. The other logic behind it is that saturated fat, especially, is associated with heart disease. Now, there's a lot of debate about that.

And so we were all told, when I was growing up, to eat low-fat foods. You know, in my family, you know, we had low-fat milk. We had low-fat yogurt. I mean, everything was just low-fat as far as my mother could find. Fortunately, we had a reasonably healthy diet, but a lot of people at that time just switched to low-fat foods that were, that replaced the fat with sugar and various other refined carbs, and guess what? Weight skyrocketed. Since I was a kid, the percentage of people with obesity in the United States has more than

tripled, more than tripled. And low-fat diets played a role in that. It may not be in the whole story, but it certainly played a role in that. And again, because just like with low-carb diets, people miss the carbs. With low-fat diets, people miss the fat. Fat is delicious. Fat makes food taste good. It makes food crispy.

It makes food salt, depending how you use it. And so there are studies, for example, which try to put people on low-fat diets, and very often those studies fail because people just can't eliminate the fat from their diet. It's hard, it's difficult. We evolved to like the stuff. So that's why I think that, look, I understand why elimination is common in diets. It makes things sort of simple and easy. But elimination diets often don't work.

We don't like them. They're often not necessary. as the great medieval chemist Paracelsa said, it's the dose that makes the poison, right? You don't need to eliminate fat. If you want to cut down on fat, cut down on fat. And furthermore, not all fats are bad for you. In fact, unsaturated fats, like rapeseed oil and all that.

They're actually really good for us. If you study after study shows that if you replace animal fats with these plant fats, your health outcomes, and wide range of health comes, are improved. You know, they're lower rates of cardiovascular disease, lower rates of Alzheimer's, lower rates of cancers. You don't have to cut out fat. Just cut down on animal fats and you'll benefit. So sticking with fat, but how we store it in our bodies, we all know that being overweight carrying too much fat, it is detrimental to our health. So you think then, well, you know, why do we do it so easily? Why do, you know, why are our bodies doing that to us?

Of course, I go into great detail about this in the book because there are a lot of very simple explanations, but the bottom line is that we evolved to be very fat creatures compared to most mammals. Our biology is different from even our closest relatives, the chimpanzees, right? For example, we have really big brains. Our brains are three, four times size of a chimpanzee, and those brains require energy constantly. Without interruption, and yet our brains don't store energy. So we have to always have an extra amount of energy on board to provide our brains without energy. So it's like having money in the bank, right?

We also have a very expensive reproductive strategy, and we're very physically active compared to chimpanzees. And so for all these reasons, we evolved to store triple, quadruple, the amount of fat that a typical chimpanzee has. Even if you're a lean hunter-gatherer in a tropical environment, right, they're 15 to 25% body fat, whereas a chimp is like 5%. And so fat played a key role in our evolution in terms of reproduction. and that means that we evolved to pack it on, right,

to make sure we have enough. But we never, you know, had Sainsbury's or Weight Roses or, you know, Whole Foods or whatever your supermarket happens to be and all these wonderful foods. So we never evolved to be able to have an excess of fat. I mean, if you look at Hunter Gathers, they're just obesity is essentially non-existent. And so we never evolved to lose it.

In fact, quite the opposite. We have a multitude of adaptations that act to prevent us from losing it. When we try to lose weight and our fat levels go down, our fat cells actually produce a molecule, it's called leptin, that drops in levels and signals to our brain, whoops, you know, get some fat, you know, gain weight back, right? And we have our stomachs, we use a hormone called grelin, and our intestines produce peptides called, you know, C-PY-Y and et cetera.

We have all these adaptations that turn on hunger and try to pull us back to our previous weight. And so dieting is really hard, and we need to be compassionate towards dieters because there's a reason it's hard. We're actually evolved not to lose weight. It's a struggle. And so it doesn't mean you can't lose weight,

but we need to be thoughtful and compassionate and careful about how we do it. So talking about how readily available food is now, there's another idea over, it's probably more than a decade or so that I first started hearing about this, of intermittent fasting in various forms. So saying, you know, we hadn't used to eat, you know, bacon and eggs in the morning, like a cheese sandwich for lunch, dinner, you know, steak and chips in the evening or something, because it just wasn't available so our bodies can't do that.

So one way of regulating our system is to eat, well, not eat, to fast for short periods of time. And that will help our systems regulate themselves. I mean, what can we say about that? Yeah, so intermittent fasting is a way of cutting calories, basically, right? But instead of regulating how much you eat, you regulate when you eat. So there are different kinds. Like some intermittent fasting, you're like, you eat normally five days a week and two days a week. You basically starve yourself, you know.

But the most common form, what I tried for the book, is called, is where you eat within an eight-hour window, right? So you basically, effectively, you basically skip breakfast and eat an early dinner and don't snack. That's essentially a good way to do intermittent fasting. And the logic behind it is pretty much what you just said, which is that we evolved to be hungry sometimes, right? We didn't just always have, you know, kitchens with pantries and food machines and whatever. Or, you know, you could just dial up and have food delivered, right?

So it's normal for our bodies to go in and out of having food and recruiting energy from ourselves. That's called metabolic switching. And there's evidence that that kind of metabolic switching has benefits. Some people think that it also will help them live longer. That's a bit more controversial because while it's true that restricting calories can extend the life of fruit flies and worms in the labs and certain kinds of mice, there's not evidence yet that it does so for humans, but there is evidence that it has some benefits.

So I think, look, I think the key is that we evolve to go in periods of where we're gaining energy, storing energy, in periods of when we're recruiting that energy, you know, what we call positive and negative energy balance. That's healthy. When you exercise, by the way, you're doing the same thing. You're going through negative energy balance. And so, you know, going hungry occasionally is probably good. And there's no evidence, really, that skipping breakfast is bad for you. It's if you don't want, if you don't like eating breakfast, you can ignore all those people tell you that's the most important meal of the day. But if you like to eat breakfast, there's also no evidence that's really bad for you either. It's, I think, you know, throughout the

book, what I try to do is point out that we oversimplify things. We have this reflexive need to come up with these magic bullet solutions. Don't eat breakfast. Don't eat carbs. Don't eat fat. Don't do this. Don't do that. And it just doesn't work that way. Everything has trade-offs. There are better foods to eat. There are better diets. There are worse foods and worse diets. But if somebody tells you there's a magic bullet solution that's just, you know, you do this one thing and that'll solve all your problems, they're trying to sell you a bill of goods. So like I said earlier, I grew up in the 1980s, which in my opinion was, it probably isn't actually, but I was going to say it was the peak period of ultra-processed foods, but probably now, isn't it?

But that was when it became really prevalent. Like I can remember, you know, three quarters of what I ate came out of the freezer and, you know, it was like fluorescent yellow. But, you know, I still ate it. I enjoyed it. So why is that? Because you can look at it in a way. if you sort of look at it in the cold, hard light of day,

you think sort of not really even food, but then why does it taste so good? Well, look, you're pointing out what is unquestionably the biggest challenge today, which is, we don't know exactly why ultra-processed foods are really bad for us, because they're probably a number of factors, and what makes them bad for you

might not be exactly the same thing as bad for me. But there's some qualities. The first is that, look, they're designed to be really appealing, just as you said, right? They're, you know, the companies have figured out how to light up our brains. You know, if you take a food and you put a huge amount of fat in it, it's disgusting, right? Or too much sugar, it's cloying, right? But you put the same amount of fat and sugar and you combine them, bam, it's like it just turns us on, right?

And then you add salt, you better, right? So they've actually intentionally engineered these foods to hit what's called the bliss point, right? That our brains just go wild. And experiments show that if you just give nutrition, and identical foods, but you kind of have these foods that are diets, but you have these ultra-processed versus just sort of normal foods. We tend to overeat those ultra-processed foods, right? So they're, they are appealing. Secondly, they're lacking fiber, which is really good for us, because fiber makes food go rancid, right? So you don't want fiber in your food. That's really bad. And they tend to

have, you know, again, added ingredients that, you know, all that sugar and fat isn't really good for us. So they're junk foods. And then finally, a lot of these foods have all kinds of things. of additives whose function and biology and consequences we don't really know or we know are harmful, like emulsifiers, right? If you have fat in your food, you need to have these compounds called emulsifiers, which prevent them from separating, right? Otherwise, your food would be disgusting, right? So the mulcifers, and we see them like guar gum, lecithin, there's all these ingredients

we see on those packages, right? Those emulsifiers not only keep the fats from separating, but they also affect our intestinal lining. and they can cause trouble in our guts. And that's just one of them, like they're stabilizers and softeners and colorants and flavorings and all these other chemicals that are added to our food, some of which may have negative effects, especially if we repeatedly eat them over and over and over again. So it's the combination of the fact that we overeat them, that they're junk food, that they have all these additives.

You add all that up and you got yourself a load of trouble. And so as ultra-processed foods have increased and there's a great, graph in the book, you know, you can just see it's not correlation is not causation, but nobody doubts that the rise in ultra-processed food underlies really the problem that so many of us have today, that the rise in obesity and the rise in a whole range of diet-related conditions like type 2 diabetes and heart disease and cancer. We, as a society, need to do something about these ultra-processed foods. They're literally killing us, and, you know, we need to take action as a, as a society to help regulate these foods because we're at the mercy of these companies that are

producing foods that we like, but we are not adapted to withstand. Yeah, so you sort of touched on this earlier a little bit with the carnivore diet, where people are fixated on, you know, essentially only eating meat. But how about the variety of the diet? You know, you hear things today, people will say things like, our healthy diet, one easy all is to eat the rainbow. And you hear things like that. You know, eat foods of different colors from different places. But you also get sort of like an extreme example is the carnival diet. And then some sort of First Nations people eat a really high fat diet. And there's even the guy

in the States who allegedly has lived on Big Macs for decades. You know, so you hear all of these different things. But surely varieties the way forwards. Absolutely. I mean, I don't think you need a professor from Harvard to tell you that. I mean, look, humans, as I said before, you know, where are the animal kingdom's ultimate omnivores? I mean, you can be a vegan, you can be a carnivore. We can eat all these different diets, but that doesn't mean they're good for us. And a lot of people, what happens is they're on a crap junk food,

UPF diet, you know, lots of ultra-processed foods. They get sick, and then they find one of these diets. And of course they're going to feel better, because any diet is going to be better than a crap UPF diet, right? And so they decide, oh my gosh, the carnivore diets for me or the, you know, the this diet's for me or that diet's for me. And, you know, they are probably better. But, you know, it takes 10, 20, 30, 40 years for a diet to affect your health sometimes. So how are you going to know, right, whether the diet that you've picked is right, the best one for you, right? That can be very challenging.

And there's no way you or I can figure that out on our own. But guess what? We have science. Fortunately, there's a lot of good information out there. We have large, huge studies, epidemiological studies, mechanistic studies. And although people sometimes claim that nutritionists can't agree on stuff, that's actually not really true. I think there's a broad agreement that diets, these traditional diets that many cultures created over the years that aren't highly processed,

the Mediterranean diet being the best studied, are really quite healthy. People on a Mediterranean diet are, you know, we have samples of hundreds of thousands of people, right, are much less likely to gain weight. They're much less likely to have cardiovascular disease. They're much less likely to have Alzheimer's and diabetes and all kinds of other illnesses. They're not magic bullets, but we have data that not only exports from a population-level

relationships, but also we have data on some of the mechanisms by which these diets are healthy. So, yeah, you can get away with a carnivore diet or a high-fat diet, et cetera. But I like to think of that famous Renaissance philosopher, Pascal. Pascal was wasn't worried about diet. He was worried about religion, right? He wasn't sure whether to believe in God, but he came up with this basic logic, which is that if you're not sure whether God exists,

and of course he was, you know, Christian, he believed in the Christian God. He said, well, you know what? You're better off believing in God because if there is one, that's going to help you in the afterlife, right? Now, I don't want to equate diet with believing in God. But if you're not sure about what to eat, You're always better off eating a diverse diet that's low in saturated fat,

that's low in refined carbohydrates, that's low in sugar, that's low in crap chemicals. I mean, that's what the data show us. That's your best bet based on a mountain of evidence. Thank you for listening to this episode of Instant Genius, brought you from the team behind BBC Science Focus. That was Professor Daniel Lieberman. To discover more about the topics we've just discussed, discussed, check out his book, Fed Up, What Evolution Reveals About Food, Diet and Eating Well. If you liked what you just heard, then please do consider subscribing to Instant Genius

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