World's No. 1 Exercise Professor: "Our Comfortable Lives Are Causing Cancer", "The Truth About Running", "Hand Sanitiser Is Making You Sick!

24:38It looks like more the latter, right? So our chimpanzees have brains, you know, typical chimpanzee might have about a 400 cubic centimeter brain, like 400 grams. Think about it in grams, right? Typical human has a brain that's like 1400 grams. So, you know, really like three to four times the size of a chimpanzee's brain. For about five million years in our evolutionary history. So the earliest hominins, hominins as a term for creature more closely related to us than a chimpanzee. So the earliest hominins, plus, you know, these astralopiths like Lucy, they had brains that got up into the 500 gram range rarely, maybe sometimes 600, but not that much.

25:21Starting around two, two million years ago, brain size just starts to shoot up if you look on a graph. Right? And that's of course around the time we started hunting, but it's really the time we have hunting and gathering. And so I think it's the whole system. It's not just meat, although meat must have been important component of it. But the whole hunting and gathering system is really a way to get more energy, right? Because you're processing your foods, you're getting more energy because you're cooking your food or you're processing it in various ways. You're cooperating, you're getting new sources of food such as meat, and marrow, and brains, and whatever.

25:58All of that together means that more energy is available, and when more energy is available, then there's less of a constraint on brain size because brains are expensive. Just right now, you and I were sitting, right? We're not really doing much of anything other than talking. But one out of every five of our breaths is to pay for our brain. Our brain is using 20 % of our metabolism. And so, to have a really big brain means you have to have a lot of energy available to you. And so most animals can't afford big brains because they don't have enough energy. With hunting and gathering, you get more energy.

26:27More energy means selection can now, you know, the constraints on having a big brain are now released. Now you can get selection for a larger brain. So individuals with bigger brains might have had some advantage over individuals with smaller brains. Maybe they were better at doing this, that or the other. And so you get selection for larger and larger brain sizes, and it really accelerates up until, you know, well, it continues up until a few hundred thousand years ago when essentially brains reached basically modern size. And then you get fat because you have so much energy and such a big brain.

27:04It's all about energy. But that kind of makes sense, doesn't it? You store more energy and then we started to get fat? Well, fat is really important for a number of reasons. One of them is having a big brain. So, you know, a human infant when it's born, its brain is consuming half its metabolic energy. Like when a kid is born, 50 % of the energy it's spending is just to pay for its brain. It's a brain on a little body, basically, right? And of course you can't stop feeding a brain. Brains require energy constantly, right? Brains don't store energy. They need a constant supply of glucose or or ketone bodies, which you can use when you don't have sugar available to you.

27:49You can get those from fats, right? So, human infants are born unusually fat. A guy named Chris Casava showed that, you know, we know that a human baby when it's born is about 15 % body fat. Way more than any other species, right? And that brain, all that fat is really kind of money in the bank to make sure that that brain always has energy available to it. And furthermore, you had published a really cool paper a few years ago, which showed that when an infant's brain is growing, right? In the first few years of life, when it's growing really fast, that's when its body fat levels are going down.

28:26And when it's storing a lot of fat, that's when its brain isn't going going much. So, there's a trade -off in energy between fat and brains as we're growing. So, big brains and fat bodies are intimately connected. So, we want to make sure our babies are fat? A fat baby is an essential fundamental human adaptation. And the body fat that we have, I mean, a typical human has much more body fat than most animals. Most primates have about 4 % or 5 % body fat. Most mammals have about 4 % or 5 % body fat. Whereas a skinny human has maybe 10 % to 25 % body fat, right? So, that body fat is not only important for brains, but it's also important for our reproduction.

29:06Because a typical mother nursing, for example, right? 100 -gatherers will nurse for about three years. Nursing is really expensive. It costs about 600 calories a day to produce breast milk. Imagine you're a hunter -gatherer and there's not a lot of food around, right? You're in what we call negative energy balance. You're not getting as much food in as you're spending, right? You can't just stop nursing. Your infant is still working to require that energy. So, you draw down on your fat reserves, right? So, having all that fat, which goes up and down and up and down from season to season, you store more fat in the good seasons.

29:40You use that up in the bad seasons. Those are fundamental adaptations to keep us physically active, to enable us to reproduce the way we do, to pay for our big brains. They're part of that, you know, our kind of relatively high level of fat, and our predisposition to store fat is fundamental to our species. We wouldn't be here if we didn't have all that fat. And I guess this is why dieting is so hot. Right, because we never evolved to diet. We evolved to put that fat on. We did evolve, of course, to use it when we needed it, right? But we never evolved to get rid of fat. It was just, it was never, you know, in an absence of obesity, there wouldn't be selection for that kind of physiological system, to lose fat without needing it.

30:28Because when we try and diet, it does feel like our bodies are somewhat against us. When I hear about sugar cravings, and you know, many people have told me that if you, the reason my diets don't work is because your body's trying to basically defend the weight that you're at because that used to mean you're survival. That's right. We call that a starvation response, right? So when you go into negative energy balance, which is what a diet is, right? You're spending more energy than you're using than you're taking in. Your body goes into a starvation response. Your cortisol levels go up, for example, right?

30:56It's an emergency, right? It's like, it's cortisol is our stress hormone. Stress doesn't cause cortisol to go up. Cortisol goes up when we are stressed, and it makes energy available to us. And one of the things that cortisol does is it makes us hungry, right? When you're really stressed at night, right, studying for an exam, one of my students, right? They get, you know, hunger, you know, they get sugar cravings, right? Because they're cortisol levels, because they're stressed, because I'm going to give an exam in the next day. It goes up, and then they want energy, right? Cortisol also makes you store fat in visceral deposits.

31:29So, so, so belly fat, which is, which is, you know, concerning, right? It's a useful kind of fat, right? Because the fat that we store in and around our abdomen is very hormone sensitive. It's, it's got lots of blood vessels, so that fat is a great energy supply when you're, you know, you're physically active, right? When I, when I went running around Central Park this morning, right, I was burning some of my belly fat. But when cortisol levels go up, that's like, it also directs us to positive, positive fat in those stores, right? And the problem with those stores is that they're also very inflammatory.

32:04So when those fat cells get too large and they swell, they become dysfunctional, and they cause inflammation. They cause chronic systemic inflammation, which is just ruinous for our health. It causes diabetes and Alzheimer's and, you know, heart disease, all kinds of diseases that, that pretty much every major disease that we're worried about, the mismatched diseases that we often talk about, are, you know, many of them are, are, are, are inflammation related. And, and, and that's why we're concerned, people are concerned about excess, at a positive excess fat, because excess fat causes inflammation.

32:43So that means that people that are more stressed and more likely to have belly fat? Correct. Yes, that's true. So that's one of the reasons why stress is, you know, a risk factor for so many diseases. Psychosocial stress is a, is a, has a pre -nicious effects. And that's why, you know, racism, discrimination, all those, all those factors that can elevate stress, commuting, have negative health consequences, because it causes us to, our cortisol levels to go up, it causes us to, us to, but fat in the wrong places, it has, a cortisol also turns your immune system down. A cortisol has all kinds of, you know, negative effects when it's, when it's long -term and persistently high.

33:29It's often been said that if you lose too much weight, for example, if a woman loses too much weight, then her menstrual cycle will stop. And I was thinking about this from an evolutionary perspective, and you was saying how, you know, fat is essentially evidence of our survival. So in some ways, is that, if that is true, then, is that our body basically stopping our menstrual cycle to conserve energy? Basically, if you could think about it like, our body saying to us, we don't have the energy to have kids right now. You are absolutely right. So it's a little bit more complicated than that, but you've, you've basically got it right.

34:04So there's two things. First of all, fat is not just an energy store. Fat is also an organ, right? Fat, fat produces hormones. We produce, fat produces a hormone called leptin, which affects appetite, but it also produces estrogen. So when women have very low levels of body fat, their estrogen levels decline, and they don't produce enough estrogen to have effective menstrual cycles. So they become what's called a menoriac. Menoriac is just a fancy medical term for loss of normal cycling. It's been shown by many researchers, former professor of mine, Peter Ellison, and their other researchers around the world.

34:48A woman named Garajna Jazanska and Poland, others have shown that, you know, our bodies are incredibly sensitive to energy availability. For example, women who are dieting, they may have plenty of body fat, but when they're dieting, which means they're going to negative energy balance, levels of progesterone, which is a very important hormone for the menstrual cycle. Progesterone is produced in the second half of the menstrual cycle and it maintains the uterine lining so you can have implantation. Progesterone levels plummet. They go down by, you know, 50 % during the luteal phase, that second half of the menstrual cycle.

35:25They're by decreasing their ability to conceive. Women who are very physically active, also there's a decrease in the amount of progesterone, again, during the second half of the menstrual cycle. An aflip way of thinking about it, though, is that because remember, what we evolved to do is to have as many offspring as possible. Our body is also, another way of thinking about this also, is that whenever there's extra energy available, the body, you know, it's an adaptation to say, hey, let's use that energy for reproduction. So that's increased estrogen levels. Let's increase progesterone levels so we can increase our for -cundity and increase our fertility.

36:04So, you know, there's a bit of a balancing act. Yes, it's a bit of a balancing act. So obviously, you know, exercise is not bad for women who are trying to conceive. And women who are, but women who are sedentary aren't exercising, have a high levels of estrogen progesterone. And that may be one of the reasons why physical activity decreases the risk of breast cancer so much. So, women who are physically active have, like, a 30 to 50 % lower rate of breast cancer. And a lot of that, part of that has to do with the fact that their hormone levels are more normal because sedentary women have abnormally high levels.

36:39But nonetheless, the important point from what you asked is that our body is incredibly sensitive to energy. And so it knows that when energy levels are low, when you're losing fat, this is not a good time to invest because think about it. But pregnancy lasts nine months. It's incredibly expensive. Then you're going to be spending months later, nursing, which is also very expensive. Maybe this is not a good time to invest. Let's wait until times are better. Then you know that this is a better use of your, of your, of, you know, better time to get pregnant. A better, you can have a much more likely positive outcome.

37:13I was thinking about what you were saying through the lens of stress as well because stress releases cortisol. And if someone is incredibly stressed, I imagine they're going to have trouble with fertility as well. Probably for the same reason. I guess it's like a line was running at you. This is not a good time to have. Cortisol, cortisol, one of the things that cortisol does is it turns down everything that you don't need to do at that moment in time, right? Because we evolved to elevate cortisol acutely, you know, for short bursts when, you know, when the lion comes into the room, right? But, but not over very, very long periods of time.

37:47So, you know, when, when the lion comes into the room, this is not a time to reproduce. It's not time to spend energy on your immune system. It's not time to do all kinds of stuff, right? Just run, right? Make it energy available. But situations where you have pre, we're persistently high levels of cortisol. Chronic stress. Chronic stress. That's what we call a mismatch, right? Mismatches are conditions that for which our bodies did not evolve, right? These are novel environmental conditions for which we are inadequately or imperfectly adapted for. And that they cause the vast majority of the diseases and problems that we encounter today.

38:23And, you know, taking exams is a mismatch. Having, you know, discrimination, racism, poverty. These are, you know, and all those sorts of things that elevate our cortisol levels for long periods of time, those are mismatches. You know, in fact, the vast majority of the diseases that people have today, apart from some infectious diseases, but the vast majority, even of infectious diseases, are mismatches because they come from humans spending more time with animals and, you know, all the, a lot of the diseases that we, you know, infectious diseases that we have, actually our diseases that jumped over from the animal world to humans, to burkylosis, for example, right?

39:02That's a disease that hunter -gatherers didn't get. It's a, it came after farming. The vast majority of diseases. I would say so. Yeah, I mean, heart disease. I mean, look, when we look around the world and look at people who don't live in modern, western lifestyles, they, they heart diseases is rare and non -existent. There's a wonderful study of a group of people in the Amazon, called the Chimane. These are horticulturist foragers, right? They have, there's like no evidence whatsoever of any coronary heart disease in these people. Some of the populations that we've studied, no increase in blood pressure.

39:37In fact, back in the 1970s, some of the first studies that were ever done on the health of hunter -gatherers found that 80 -year -old hunter -gatherers in the Kalahari had the same blood pressure as 20 -year -old hunter -gatherers in the Kalahari. And they compared them to, to, to, to, to English people and, you know, the Londoners at the same time. And of course, by the time you're 70 or 80 in London, almost everybody's hypertensive, right? This is, this is a, this is because of diet and physical activity and, and probably also stress. These are, these are things that have changed in our modern world for which we are very poorly adapted.

40:14No diabetes. If it exists, nobody's diagnosed it. It's probably incredibly rare. But even a few generations ago, diabetes was rare. I mean, diabetes is the world's fastest growing disease. Where I work in Kenya, in, in the area around the town, city called Eldoret. When I first started working there, gosh, long time ago, you know, you drive into the city and you'd be an Eldoret. But now as you're driving to the city, you pass by all these diabetes clinics. They weren't there before. That's because diabetes is rising in, in Africa to, at incredibly rapid rates, which, you know, isn't so surprising.

40:55Because diabetes in places like the United States and England are incredibly common. So they're like 12 % of Americans have diabetes now. You said that this mismatch is responsible for most diseases. Doesn't that therefore mean that I'm most likely to die from a mismatch disease in my life? Yes. Okay. Yes. The vast majority of us in, in the Western world will die from a mismatch disease. The number one disease in the world today that kills more people than anybody, anything else, is, is heart disease. And as far as work, you know, heart disease is, kills at least about a third of us. Cancer is number two.

41:29Cancer is of course our ancient disease. So not all cancers are mismatch disease. But many cancers are mismatches, right? Breast cancer, which is much more common in Western populations than in non -Western populations. But heart disease, you know, is essentially as far as work concern non -existent until fairly recently. And now it's killing about 33 % of us. You said a third, right? Yes. That's crazy. It's so crazy. That's the bad news, right? But the good news is because they're mismatch diseases, they're not, they're not inevitable, right? We shouldn't just say, all right, heart disease kills a third of us.

42:05That's just because the amazing thing about heart disease is that diet and exercise can prevent a large percentage if not almost almost all of them, right? If people who live in environments where they don't eat a piece of genetic diets, diets that are that make people overweight, diets that lead to metabolic syndrome, diets that are, that are atherogenic that cause atherosclerosis, right? People who are physically active and stress is also an important role, plays a role in heart disease. Don't smoke. Have vastly lower rates of heart disease to the extent that it's, you know, this is a, this is a, this is a disease that doesn't have to exist.

42:49You said you're writing a book about diet and food. Yes. Why? The story of how the diets that we eat today and is actually really fascinating story. But also because I think that we, if we take a more evolutionary approach to diet, we can, I think, do much better to thinking about, you know, help people make choices. I mean, one important point to make is that, you know, today, like when we finished this interview, I'm going to go home and my wife and I are going to, and my daughter and my mother in law are going to try to decide what we're going to have for dinner tonight. And we can, like, we can go, we can eat whatever we want, right?

43:31We can go to the supermarket and there's like, you name it, right? Here in New York, there really is you name it, right? We can, we can go out to restaurants. We can have Chinese or food or Japanese food or American food or French food, whatever, right? We have, we have incredible choices to us. For most of human evolution or history, people never chose what they ate ever, right? They ate what was available to them. And now with all this choice, we come, comes, comes bad choices, right? And so I would like to help people figure out how not only realize that these choices that we have to make are, we're not really evolved to do, but also how to better understand what those choices are and what the complexities are of them.

44:13Because there are no, there's no such thing as a free lunch, right? Every, every choice that you make has alternatives and alternative consequences. And I think people oversimplified diet. People come up with simple ideas, you know, just do this. Just be a vegan. Just be a this. Just be a that. There are no perfect answers. Do you think in some ways that our culture moved so much faster than our biology in a sense because we're like super sedentary now, we just sit all day. We have these screens that bring us our food. The food is processed. And is this part of what's causing this sort of misalignment all these mismatched diseases as you call them is.

44:50Absolutely, because evolution by natural selection occurs really slowly, right? Every generation, people with genes that have given them adaptations that are better able to handle a particular environmental context do better than the next generation. So slowly, slowly, slowly, generation by generation, you get change. And that's true for every animal, right? All mismatches not unique to humans, right? As environments change, some animals are better adapted to that environment than other animals. And though those animals are going to be more likely to pass those genes on to their offspring. So mismatches are part of a natural selection.

45:28Every species as environments change is subject to mismatch or as they move into new environments. The difference with humans is that we have culture. And culture has caused an acceleration of environmental change, right? Think about, I mean, just today, right, I have now in my pocket a computer, right? I didn't have a few, you know, decades ago, right? We have internet and email and all kinds of things, right? Just the last few decades the world has changed amazingly. Just think about the last few generations, the last few hundred years, the last few thousand years. So cultural evolution is so powerful and so rapid, it's so fast, it's so transformative that we have made our world so fast, vastly and rapidly different that our bodies cannot possibly keep up in terms of our biology.

46:15It's this mismatch. It's this difference between evolutionary biological change and cultural change that has heightened the kinds of mismatches that we exist. And then guess what we do, right? So we, let's say we, I'll give a very simple example, right? Until recently nobody read, right? And nobody spent a lot of time indoors. And so myopia used to be extremely unusual. Myopia is having is being near sighted. So if you go to like, there's a famous study where they looked in in in any way populations, right? Nalaska, and they looked at grandparents and grandchildren, the grandparents all had perfect vision and the grandchildren all need glasses, at least a large percentage of like 30 % of that, right?

46:54In various parts of the world, the number of people who are near sighted has gone up in some parts of the world. It's 50 % in America and England is probably about 30 % of us need glasses. But this is all recent. In fact, the first study this was done on the Queen's guards, you know, they're actually now the King's guards, right? So, you know, those, they have the their skin hats. I don't know what kind of fur it is on their head. Anyway, they're the ones who stand in front of Buckingham Palace, right? There was a study done in the early 1800s, which showed that it was the officers who had a higher percentage, like a large number of the officers had to wear glasses.

47:30But the foot soldiers were all fine. And there was something about it, right, that about the officers and then people started studying them around the world and and then initially it was thought to be reading and now we know from more careful study is that's really spending a lot of time indoors when you're young that causes myopia. So we never evolved to do that, right? So we're more prone to myopia. But it's not a big deal because guess what we just go to the optician and we get glasses and we can deal with it. And you know, it's not doesn't really have really any major effect on our on our health or our longevity or ability to find a mate, etc.

48:07We all do just fine. Can we undo it? Well, here's the thing. I mean, what we're doing in note myopia, you know, you can get lasx surgery and there are some things you can do very expensive. Most people can't afford it, right? But the point is that we're treating the symptom with when you get glasses, you're treating the symptom not the cause, right? But it's okay, right, because it's just glasses, right? The problem is that for many mismatched diseases, right? When we still we're treating the symptoms rather than the causes, right? So cancer, cancer, right? Or or many forms of heart disease, right?

48:42You don't see a doctor in our in our medical system until you get sick, right? And then you get pills to lower your blood pressure and pills to lower your cholesterol, etc. But these aren't, well, those some of them can be preventative, but to a large extent, most of medical treatments are treating the symptoms diseases after they occur. And of course, we should do that. We should alleviate pain, we should alleviate suffering, we should try to decrease people from dying from all kinds of diseases. But wouldn't it be better if we actually prevented those diseases in the first place, right? We would have a much more effective medical system.

49:19So what we're causing, in my opinion, kind of a new form of evolution, I call this dis -evolution, where by where treating the symptoms of mismatched diseases, thereby enabling those diseases to remain prevalent, right? And in some cases get worse because we can now cope with them, right? So people now get diabetes, we give them metformin or whatever, various kinds of drugs, they get heart disease, we give them various, you know, pills to kind of keep them going. They get myopia, we give them glasses. All of these are things we should do, but wouldn't it be better if we prevented people from getting heart disease in the first place?

49:58Because this is one of the big questions I always have with evolution, and when we're talking about our evolutionary history, is, is always still evolving? And from what you said there, it sounds like we, in a way we are, but it doesn't sound good, it sounds, you say, de -evolution, sounds like we're in some way. Dis -evolution, yeah. Yeah, I mean, there is a little bit of selection going on. I mean, you can't stop selection, it's like gravity, it happens. But it's slow. What we, in Howie, I think it was James Nester that said, the way we chew impacts what our face looks like when we become adults.

50:28If a baby's chewing lots of soft foods, when they grow up they're going to have like a small jaw. Yeah, that's research I did actually. Oh really, I think you cited you. Yeah, so how you chewing affects the shape of your, how are your jaw grows? And so it is true that we have smaller jaws today than we used to. The good news is it's not that bad, right? It doesn't really cause that much. You maybe have teeth more likely to have malaclusions, et cetera. But you know, you can, but we can go to the orthodontist and have our third mullers extracted, et cetera. I mean, we can, we can cope with that, right?

50:59It's not, that's not the worst thing, right? Of course, he thinks that it causes us to breathe through our mouths and all that sort of stuff. But it's not the kind of disastrous sort of mismatch that occurs from say, you know, well, this is controversial. But the evidence, you know, the vast majority of the evidence suggests that if you eat a lot of sugar and you eat a lot of saturated fat, you're more likely to get heart disease, you're more likely to get plaques in your arteries, right? If you don't aren't physically active, you're, you know, do exercise or physical activity, or your blood vessels start stiffening and you start becoming hyper -tensive, right?

51:36These are all, these are all aspects of our environment that, that we have the potential to, to, to control better and to prevent disease. Do you think we've gotten to a bit of a bad habit as a society of just throwing a pellet the problem? Yes. I mean, that's, that's the fundamental argument of, argument of making about disavolition. And then, then, you know, it's just, it's expedient to treat the symptoms of a problem rather than its cause. What's the problem with that? Well, because, number of reasons. One is, it's, isn't the, the best diseases the one that you never get in the first place.

52:12So, so we can keep people alive once they get heart disease. We can keep people alive once they get arthritis. We can keep people alive once they get all kinds of diseases. But they, but they're, but their quality of life goes down. And of course, we pay for it. We pay for it out the nose, right? It's something like 70, 80 % of the time when somebody goes into a doctor's office, that's for a preventable disease. 70, 80 % of the time, right? That's an astonishing amount of money that we spend in our medical system on essentially mismatched diseases. It's bankrupting us, but it's also causing misery.

52:48And it differentiates people of low income and people who are, suffer from discrimination. I mean, look in the United States, right? Who gets the chance to exercise and eat, you know, fresh vegetables and, you know, high quality foods and non processed foods. It's, it's wealthy people, right? So it's also, it's just unfair and unjust. You mentioned cancer. In what way? And how do we know that if that's a mismatched disease? Well, cancer is not completely a mismatched disease. I mean, you know, all species that are multicellular get cancer. Cancer is a, is essentially a disease of evolution going wrong, right?

53:27Natural selection going wrong, right? So instead of, you know, when you have many different kinds of cells in your body, when a cell becomes essentially selfish and starts to outcompete other cells because of mutations it gets, that's a cancer, right? So cancer is an outcome of multicellularity. Dinosaur has got cancer. We have evidence for bone cancer and dinosaurs. So it's, we're never going to get rid of cancer completely. But we also know that cancer is very much a disease of energy, right? When, when people move to high energy environments, they're much more likely to get cancer. More food, more food.

54:04More food. Physical inactivity is a major risk factor for cancer. Insulin, for example, high levels of insulin insulin, you know, promotes, you know, anything that promotes mitogenesis, you know, which is mutation, you know, cells to divide is going to increase rates of cancer. Also, anything that increases the rate of, you know, that a lot of the cells that could get cancer are cells in our bodies that interact with the outside world. So our lungs are guts, you know, our colons were, you know, things from the outside world coming to contact with them, skin exactly. Those are cells that often get cancer.

54:40So when we have carcinogens, you know, poisonous toxic compounds in our environment, those can elevate levels of cancer. So smoking, car pollution, et cetera, those can cause cancer. But also having lots of energy. So we talked earlier about when women are physically inactive, they're, they're, their hormone levels shoot up, right? Because the body says, haha, more energy. Let's spend it on reproduction, right? And there's a trade off there more in the higher levels of estrogen progesterone increase the rate of breast cancers that occur. Because, because they cause more, more turnover on those cells in the breast tissue.

55:17And that's, that's why those, those cancer rates are higher. So you can, there's famous studies which show that you look at women from Bangladesh who live in Bangladesh, women from Bangladesh who move to England, or Bangladesh, women who are born in England and live in England. Where every, no matter how you, how you look at it, Bangladesh, women who move to England, their cancer rates go way up. The difference, a major difference is energy, you know, the diet that they have, the physical activity levels they have. They're using more, they put more weight. Cancer rates just shoot up, cancer. So if you actually plot GDP of countries against cancer rates, it's a, it's a nearly straight line.

55:54A richer the country, the higher the rate of cancer. What about hunter gatherer women? Did they have less ovarian cancer? That's a hard thing to measure because diagnosing cancer requires some sophisticated technology. And to my knowledge, nobody's ever done careful studies of cancer rates among hunter gatherers. But most of us are pretty convinced that cancer rates are much, much, much lower among hunter gatherers. But again, also the population sizes are tiny, so you can't really get very large samples. The amount of menstrual cycles you have is major factor, right? So I believe I hope I get the numbers right?

56:30Typical woman today who goes through her entire reproductive lifespan will have something like 500 menstrual cycles because of birth control and and smaller families. It's just 350 to 400 in your book. Does that what it says? Okay. Thank you. Okay. It's it's in the hundreds, right? Typical hunter gatherer is going to have something like 50. 50? Yeah. In her entire life. And every time you go through a menstrual cycle, your your body is being exposed to high levels of these hormones, right? Birth control and sort of modern family planning, which you know, I'm not obviously a poster, but it is another factor that has probably elevated rates of breast cancer.

57:15I didn't I never knew that. I never knew that having more cycles reduced your. Sure, because each every cycle involves, you know, surges of hormones. That's what causes the cycle. First you have an estrogen surge, then you have a progesterone and an estrogen surge. Of course. That's that's what happens across the menstrual cycle. And how to gather a women would have been pregnant more often more of their life? Well, yeah, they typical what we call a natural fertility population, a population that doesn't use birth control. Women are most of the time pregnant or nursing. And they go through short periods when they are doing neither and then get pregnant again.

57:57So so the number of and and you don't of course have menstrual cycles when you're pregnant. And you're generally don't have menstrual cycles when you're nursing until again, it's your energy level. So so because nursing costs so much energy that high energy demand of nursing suppresses a very in function. So so so so nursing women are often a menoriac. They're not cycling. And that's not just a very cancer that's breast cancer as well. Yeah, it's you know, it's but yeah, any any any cells that are sensitive to estrogen and progesterone those those are the cancer those those particular kinds of so often when you you you measure breast cancer.

58:37So you talk about you know, whether the the cells are estrogen or progesterone sensitive. I wanted to talk about how our body stores energy because I think that in part. Answer a lot of these questions around the things we're discussing about weight loss about diet about all those things we've talked about previously. I have a very loose understanding of this. So please enlighten me, but I did go keto for eight weeks and I lost so much weight. It's pretty crazy. It bounced straight back. Of course. Yeah, because you mostly lost water. Oh really? Yeah. That's one of the problems with many diets.

59:11So so fat is a is a fat is a wonderful molecule, right? It's we tend to demonize it. But it's it's fat is life, right? That is a really important molecule. So a fat is a is a fat molecule has a backbone of something called glycerol glycerin, right? It's a three carbon molecule. There's a carbon carbon carbon and they're stick their little hydrogen sticking off. And to each one of those carbons is a chain a sticks off a chain. What's called a fatty acid? So so they're called tri glycerides. There are three fatty acids on each glycerine. And there are different kinds of fatty acids like they're saturated fatty acids and unsaturated fatty acid.

59:51We can look around those whatever. But the point is that these are each fatty acid stores a huge amount of energy because those long chains of carbon. What our body does is it cleaves those carbons into smaller units and gets and we get energy from that from the bonds between those carbons. That's basically what our mitochondria doing, right? So fatty acids fats in general have store a huge amount of energy. They store twice as much energy as carbohydrates per unit mass. So what we do is we eat foods that have fat in them or we eat carbohydrates and our livers convert them quickly to fats. It's easy, right?

1:00:28So that's why you know, fat free diets don't prevent people from being fat, right? Often with the help of insulin, but it's not the only hormone involved. We then we want to store those if you're not burning them, right? Our body can either burn them or store them. So if we're not burning them, you were running or gesticulating talking, etc. We're going to store them and we store them in special cells called adipocytes. Those are the fat storing cells. And our bodies have billions of them. You're born with billions of these, but you only have so many adipocytes. You get them when you're young, when you're born, and that's it.

1:01:02That's the number of adipocytes you have for the rest of your life. And so those adipocytes, so insulin, for example, helps potentially the movement of triglycerides, right? Which you want to break down and then you transport them into the fat cell, and then you reassemble those fats in the fat cell, the glycerines and the fatty acids. You reassemble them in the fat cell, and they swell like a balloon. So every little fat cell in your body is like a little balloon filled with fat. And it's there to be used. And then they're at hormones, which then help us retrieve that fat when we need it, right?

1:01:38When we're running a marathon or just sitting around talking without having a head lunch for a while or whatever. And so, you know, we store fat, we then burn fat, we store fat, we burn fat, we store fat, we burn fat, et cetera. And that's normal, right? And as we talked about earlier in this conversation, humans evolved to have an unusually high level of fat. So a typical hunter -gatherer male will have about 10 to 15 % body fat.

1:02:05That's normal sort of skinny human being. That's way more than most mammals, right? So women have more. Women have more, right? So women have a higher percentage of body fat, although actually women tend to be smaller bodies. So the total amount of fat that men and women store is about the same. Women, of course, if you think about it, because they're involved in, they're the ones who have to pay for reproduction, and directly either during pregnancy or nursing, that fat is especially important for reproduction, right? So what happens is that that fat is there, and it's like a bank account, right?

1:02:42It's energy that we store and energy that we use. And we start in different places. Most of the fat that we store is what we call subcutaneous. So underneath the skin, subcutaneous. But we also store fat that we call ectopic. That's outside of where it should be. Some of that fat is, and a lot of that ectopic fat is some of that's in our liver. We call that, so people have a lot of, so normal livers have just a little bit of fat in them. But if you have too much fat in your liver, your liver starts to malfunction. It's called non -alcoholic fatty liver syndrome. You can have fat around your kidneys.

1:03:13That's what suede is, right? But too much fat around your kidneys, again, causes problems. Fat around your heart, fat around. So all that fat in your abdomen, we call that visceral fat. Visceral means guts, right? So that gut fat is very problematic. And because when those fat cells get too big, so if you store a lot of fat beyond those sort of normal levels, as the fat cells get bigger and bigger and bigger, just like any balloon, they start to rupture. So, you know, if you overfill a water balloon, it's going to break. If you overfill on a depocyte, it's also going to start break. And when it starts to break, it attracts the immune system.

1:03:52And the immune system comes in. White blood cells come, right? They think, so something's wrong. We have a, we have damage here. And they start to produce molecules that trigger a system -wide immune response. And the fat cells themselves also will trigger an immune response. The fat cells can produce the same kinds of molecules that our white blood cells produce. So the white blood cells are produced, molecules called cytokines. Cytophersel, right? Kind for enzymes that do something, right? And so the ones that fat cells produce, we call them adipocines. And like one adipocine that produces called, is a TGF alpha, right?

1:04:37You may have heard of. And that turns on your, it's like, it's like, it turns up the dial on your, on your inflammatory system, right? And it goes everywhere in your body. And you start getting inflammation, right? And that inflammation, for example, if it's those turns, if you're, if you have inflammation in your, in your blood vessels, then that inflammation can help cause plaques to form in your arteries. If that inflammation occurs in your brain, those can cause plaques in your brain that can cause Alzheimer's. If that inflammation affects receptor cells on muscles, et cetera, that can cause insulin resistance, which can cause diabetes.

1:05:15And the list goes on, right? So that chronic inflammation, which can be caused by too many fat cells that are overpacked, essentially, is, is why too much fat can, can be, can cause health problems. The keto diet and fasting, they, someone said to me that the day that keto is basically a form of fasting in a way. And are they, how do they help the body? Because people are pretty crazy and pretty keen on both fasting at the moment, but also the ketogenic diet. Well, fasting is when you go into negative energy balance, right? Which is how we spent most of our sort of evolutionary history, right?

1:05:54Well, you, how you spend part of every day, right? We, we eat. Well, after you eat, you're in positive energy balance. And then when you, in between meals, your energy balance goes down, right? Now you're, you're burning now energy that you've stored. When you're asleep, you're in negative energy balance. So fasting is just a prolonged state of negative energy balance, right? Does that mean that it would reduce my chance of getting cancer? Could do. People are, are hoping that's the case. I don't know how good the data are for intermittent fasting. Because if the surplus in energy causes cancer, then me being in that negative energy balance presumably will reduce my chances of getting these right.

1:06:30But then you have to go back into positive energy balance at some point too, right? You can't keep up negative energy balance. So intermittent fasting isn't necessarily a way to lose weight if you eventually, you know, replace those calories, right? So what you, so here's a hypothesis, right? To which I cannot, I cannot prove. But I think that, you know, when you, when you exercise, right, you're also going to negative energy, negative energy balance, because you're burning energy, you're not eating while you're exercise. These most people aren't, right? And, and your, and your body's turned, you know, turning on all kinds of mechanisms to, to cope with that negative energy balance, you're turning on all kinds of repair and maintenance mechanisms.

1:07:10When you, when you go through intermittent fasting, you're basically doing the same thing, but less acutely. It's a more gradual level. And I, and if you look at the, at the, at the genes that are turned on by exercise, and the genes that are turned on by intermittent fasting, many of them are very much the same. And I think it's because you're basically turning on genes that are responding to that negative energy balance. But, but I would argue that you're going to get more of a bang for your buck by exercising than just going through intermittent fasting. Well, I think a bit too much. Yeah, I mean, intermittent fasting might be kind of an easy way to get some of the benefits of exercise without exercising.

1:07:48It might be. I mean, obviously we went, we, you know, there's nothing necessarily wrong with intermittent fasting, but I'm not sure that it has some of the huge benefits that people claim. Now, keto diets are little different, right? So keto diets are when you're, you're basically avoiding any carbohydrates. And carbohydrates, the basic building block of most sugars is glucose, right? Glucose is the sort of simple form of sugar that are basically in starches. There are some other sugars, fructose is also, which is the kind of the sweet one. But when you basically stop taking in glucose, right?

1:08:22You're now basically taking in only fats. And so instead of using glucose to fuel your brain and other cells in your body, you're now using what's called ketone bodies. These are essentially, remember, we talked about how you, when you break those fats down into small little units, those are ketone bodies. They, they can be used as energy, but there are more of a kind of a backup energy source for our bodies than the primary energy source. So we, we use them, our bodies tend to use them when we don't have glucose available to us. And does that mean the same sort of repair and restore mechanism kicks in potentially?

1:08:59No, I don't think so, because it's not negative energy balance. You're just using an alternative fuel in this particular point. Because a lot of doctors have sort of prescribed a key to diet for people that have like epilepsy to exceedures. Right. And I don't think anybody knows, I'm not a neurologist, but I don't think anybody knows why keep, keep high ketone diets are so beneficial for epilepsy. But it could be that they do, and I just don't know it. It's not my, it's not my subject. But anyway, there's a, there's a, there's a thought that if you just, you know, essentially keep your insulin levels low and rely on ketone bodies instead of glucose, you can, you know, do all kinds of miraculous things.

1:09:36For weight loss, if you look at the data, yes, it does tend to lead to rapid short term weight loss. But the data don't, don't show it is very effective as a long term weight loss strategy. And I think your, your example, your own anecdotal account is sort of typical. Are we too coddled? Are we coddling our kids too much and coddling ourselves too much? And is that causing some of these mismatched diseases? Well, I'm not a psychiatrist or a psychologist. So I physically coddled. Oh, physically coddled. Stopping kids from doing anything that might hurt them or, you know, the risk of version and.

1:10:13Yeah, I think so. Yeah, I mean, the comfort industry. Absolutely. I mean, you know, I have a whole chapter in my book on comfort, right? We have this idea that comfort is somehow good for you. Like, where does that come from? Right? Comfort is nice, but, you know, I mean, who wouldn't rather be in business class than in economy? Right? But, but is a comfortable shoe better for you? Right? Is it sitting in a chair better for you than walking around or standing? Is it better to take the stairs or take the lift or the elevator? So comfort isn't necessarily good for us. But when we, but we now in a live in a world where we're able to have incredible levels of comfort.

1:10:45And, and it's definitely not doing us some good because, you know, kids need to run around. I mean, every kid needs a good hour of physical activity a day. To build a healthy skeletal system and to, you know, for all the other benefits that come from physical activity. So preventing our kids from running around and doing physical activity is definitely a problem. Is there any evidence that our kids are getting sort of physically weaker or physically? Oh, absolutely. Absolutely. I mean, we have data in the United States. We have this thing called the presidential fitness test, right? That was started.

1:11:13I think maybe it was Kennedy started. I can't some president a long time ago started it. So we have decades worth of data and kids today are less fit. Absolutely. Any ask any army recruiter? They'll tell you that fewer and fewer army recruits are physically fit and able to be strong in terms of bones and skeletal structures. Yeah. I mean, the rates of osteoporosis are going up. And one of the reasons for that is that, you know, loading our skeleton when we're growing up causes the skeleton to accrue mass. To grow bone. If you don't, if you don't exercise, right? And especially weight bearing forms of exercise, you don't grow as much skeleton.

1:11:50And then when you hit, you know, normally people stop adding bone around 25 to 30, right? So I don't know how old you are, but you're. 51. All right. So you're, yeah, that's it. You have no more bone to add in the rest of your life. You're going to start losing bones, right? But fortunately, you look like a reasonably fit person who was very physically active. So you probably built up enough bone. So having a high level of bone when you're in your 20, when you're 25 to 30, as you lose bone, that's going to protect you from falling below that threshold that's going to give you osteoporosis. But if you aren't physically active when you're young, you have less bone to start with.

1:12:24You're still losing through the lose bone. And you're going to be much more likely to fall below that threshold. You're much more likely to get osteoporosis and rates of osteoporosis are rising. Again, it's another one of these mismatch diseases that's rising radically throughout the world. Exercise also helps prevent bone loss because it suppresses the cells that essentially cause our bones to start being resorbed. So so it's a it's kind of a double whammy. You know, not enough exercise when you're young, you have less peak bone mass, not an exercise when you stay old, your bones are going to lose mass at a more rapid rate.

1:12:56I was reading in your book that teen tennis players can become 40 % thicker and stronger when they become older because they were using it in the arm that they use. Yeah. So so when you play tennis, right, the arm that you use, which is whacking the ball, that's getting more loading than the arm that you simply use to throw the ball in the air. So there's a symmetry. So the humorous, the upper arm bone of tennis players can be like 40 % thicker in the arm that they use to whack a tennis bone. Just the bone. Yeah, it's it's a beautiful experiment, you know, natural experiment in our body to show the importance of loading that that loading causes your your skeleton to respond because our skeletons are like other tissues in our bodies responds to demand, right.

1:13:40We match capacity to demand if you don't demand something of a tissue, it's not going to grow the capacity because otherwise it's going to be wasting energy, right. I know that about muscles. I knew that that muscles grow and expand, but I didn't think my bones. I had any say in the development of my bones. Absolutely. Yeah, loading your bones is is is is one of the factors that just we talked about it earlier. That's why people who eat harder food, you know, that's less processed grow larger jaws, right. Our jaws have shrunk by about 6 % we showed by about 6 % since we started processing all our food because we're just loading our our jaws less, right.

1:14:17That's another example. Is there a consequence to this? Well, so when consequences increased rates of malaclusion, right. There's just not enough room for our teeth to fit into our jaws. So now we have to go to the you have to go to the orthodontist get our wisdom teeth removed because there's not enough space for them. Because okay, so if I just get my kid chewing hard food from the jump, then he his wisdom teeth will be fine. It might be the case. Yeah. So so the experiment I'd like to see somebody do Christmas unethical. It would be to randomize two groups of kids have one group of kids basically chew really hard resinous gum for like all their childhood, right.

1:14:52Because you're not going to get them to eat like, you know, unprocessed hunter gather food, right. But we haven't chew gum all the time and then compare them to say their twins who don't chew that much gum. And let's see who you know see see how much of it affected has on their jaw growth. Pubety, puberty, the age in which women go through puberty has changed quite significantly. Yeah, I couldn't figure out why it's kids energy again, right. It's always it's about energy. Remember life is about energy taking in energy and using that to reproduce. So so how much energy you have when you're growing up affects the rate at which you grow on the rate and the in your ability to switch from growth to reproduction.

1:15:33So we have data, for example, from France, there's good data from hundreds of years in France. I'm not sure why the French have such good longitudinal data, maybe it's because of Napoleonic army or whatever. But we can show that you know 200 years ago French girls were tending to go through puberty. They would start their menstrual, you know, they went through what we call menarchy when they start menstruating around the age of 16. Today it's around 12 12 and a half, right. And that's because of more energy. We see that in the area of Kenya where we do feel work right there. We're looking at the same population, Collision speaking people.

1:16:05And they're in the rural areas where you know they have a hard lives right there. They're working all day long. There's no machines. There's no electricity. There's not a huge amount of food girls. We go through menarchy about two years later than in the urban area just you know 50 kilometers away where there's more food. There's more energy. There's more Coca -Cola. There's more whatever. They and we call that the secular trend right so that girls are maturing earlier. They can reproduce her because again what does natural selection want you to do. Once you take an energy and use it to reproduce that's what we're adapted for.

1:16:40So if you have more energy, we're involved to do it earlier. Every time I have these conversations I realize that I'm sat in a chair for a living for sometimes three hours at a time. Today I've been sat in this chair for about seven hours. And I go, this is not going to be good for me for a long time. If I do this podcast for the next 10 years maybe I should just wrap it in here. I mean it's been a good run. Does it does it matter that I'm spending so much time sitting down? Is there any evidence that this is going to you know have an adverse effect? Well, so the evidence is that if you so people who sit more can be an issue.

1:17:13But there's two issues. One is that if you look at the epidemiological data what really matters is a leisure time sitting versus work time sitting. So people who have who sit a lot at work but then also sit a lot in their leisure time when they're not at work. They're the ones who want run way more risk of disease than people who are just sitting a lot at work. So that's one issue. So I think you're probably okay because I can tell you, you know, I know that you're obviously very physically active. You work out, et cetera. That's going to help be very protective. But the other issue and I think we talked about not my in the previous interview was sitting about so so how long you sit for a particular period is also very important.

1:17:53So we should be getting up every 20 minutes. You're going to be interviewing Dave Reichlin in a few days. So Dave Reichlin published one of my favorite papers ever who showed that the HODSA sit just as much as Westerners. They sit about 10 hours a day. But they get up all the time. If you're in a HODSA camp, you know, there's babies running around. They get up to get the babies. They're getting around to 10 the fire. They're getting up all the time. Nobody sits for a few hours and just like does what you and I are doing. And when you get up you're kind of turning on metabolism of your body. You're turning on your muscles.

1:18:23It's like turning on the car engine, right? You're you're you're kind of awakening all kinds of metabolic processes and that seems to have a huge amount of benefits. So the key is if you're going to sit get up a lot. Go get up go go pee make a cup of tea whatever you know interrupt your sitting. A lot of it. And of course if you're going to sit at work, make sure that you're not spending you know sitting in your car to get to work isn't good. And then you go home and you sit on the couch and watch television. That's not good. So you know make sure that those non -work periods of time are don't involve too much sitting.

1:18:58Is that why we've got so many of these random pains joint pains, you know, we were talking about you said back pain is the. Which is the number one medical complaint in the world here back pain. And that surely is because of the way we've designed our chairs and our lives. Well, a part of that is also just back strength. So we you know I'm sitting in this lovely comfortable chair here and I'm resting my back against it. I don't have to use any of the back muscles right. So we we develop weak backs that don't have any endurance so they're quickly fatigable right. So and actually the best predictor whether somebody gets back pain is how strong their backs are not just like.

1:19:36Like you know a cute strength like from doing you know like one thing is it's how how how how how much endurance their back muscles have because because. Just think about it like I don't know you but I can't even once in a while I get a back pain right I bend over to pick up a pencil or something like that. And I think it was picking up the pencil right but that's just the straw that literally broke the camel's back. It's it's really the fact that I just it just happened to be the the event that triggered it but it's when my back is weak right that I'm just more likely to do something a little bit weird and then trigger something that causes a spasm right.

1:20:12But having a strong back muscles is the way to really to prevent back pain. If there's someone's just had everything you said about these mismatched diseases there's a lot to take it you know there's a lot of different mismatched diseases you said that if you're going to die from anything it's basically going to be one of these mismatched diseases. Is there a conclusion is there an actionable conclusion about something maybe that I can change or do today or is that there are philosophy you can lend me. That is going to reduce my chances of getting one of these mismatched diseases just like a broader philosophy toward the life.

1:20:46Yes I well to I think there's two the first is that understanding why we get particular kinds of mismatches helps us make decisions about how to use our bodies right what to eat how to be physically active how to sit. I mean all the things that we've been talking about result in action items right let's get up more often right let's. Let's not eat sugary fatty foods so often right let's you know let's try to avoid psychosocial stress which is you can't just you know wave a magic wand and do that that's a hard one but we think that our life is normal we think it's normal to live the kinds of you know everybody thinks their normal life is normal right we think the foods that we eat are normal the kinds of physical activities that we do are normal the clothes that we wear the shoes that we wear are normal cars all of that right and but.

1:21:38From an evolutionary perspective they're not normal that doesn't mean they're not good or they're not necessarily bad right but but it's it gives us a chance to pause and think and ask you know do we have to live with this right or or how can we modify the way we use cars and taxis and shoes and you know we can don't have to get rid of shoes but maybe we be better off with more minimal shoes especially for our kids maybe we be better off without you know processed foods that are have all the fiber you know removed and all of that we're going to be able to do that. All of you know that fat and sugar added and all kinds of other crap right again that's not engage in a paleo fantasy and pretend that hunter gatherers don't get sick or that you know hunter gather you know what if eating like a hunter gather will make you you know absolutely healthy that's not the way it works but we have information that we can learn from our evolution and history that helps us make better decisions so that's point one and point two is that we need to be really aware of this vicious cycle that we've created in our modern world whereby treating us with the symptoms of these mismatched diseases are actually driving forward the system and making things worse there's a reason that heart disease is going up in the world there's a reason that diabetes is going up in the world there's a reason that myopia is going up in the world right because we're we're creating novel environments for which our bodies are poorly or inadequately adapted and then instead of preventing those causes where simply when we can treating the symptoms and and so we're not stopping that you know the the the fundamental problem from occurring and and thinking about it that way from a kind of modern sort of cultural evolutionary perspective it's not a form of natural selection it's a kind of cultural evolution that's going on but it's cultural evolution that's affecting our bodies and thinking about that vicious cycle that we've created can help us stop the vicious cycle.

1:23:24Q1 is often when businesses start implementing new systems and processes in hopes of creating efficiencies for the year ahead and over the course of my career I've learnt just how crucial having the right systems in places one which has helped me across many of my investments is net suite that also a sponsor of this podcast net suite is the number one cloud financial system through their streamlined platform you'll find all of your accounting financial management inventory and HR in one place their technology has been a real game changer especially for my team up flight studio as over the last year we've moved out of startup mode and into scale at mode we no longer have to juggle multiple systems and having everything together has reduced the number of manual tasks and errors over 41 ,000 businesses have chosen to future proof their business with net suite so if you'd like to learn how it can help your business head to net suite dot com slash Bartlett and free download the CFO's guide to AI and machine learning that's net suite dot com slash Bartlett thank you so much Daniel I as you are speaking I was just thinking about something we haven't discussed but that is front of mind for me at the moment which is the cosmetic products that are in my life I spray all this geogen on my pores and I put all this these chemicals on me and there's a whole industry that are telling you to rub these creams into your face and all of this stuff and alcohol in your mouth with mouthwash and it over the last three months since we last or each other I have really started to rethink about all these chemicals that I just assumed we're all meant to like throw down our mouths up our nose and you know what I'm saying yeah is there anything that you've learned like any advice I need on that stuff just be skeptical skeptical I mean look there's an entire world of people out there who's trying or trying to sell us stuff right and and if you're particularly like you you're you're you're you're you're you're clearly interested in how to live your life better right so I think you're especially vulnerable to people with the latest big idea the latest new product because you're you're a seeker right you're you're looking for this stuff right so you're you they've got you you're in their target right and you're you're I think more vulnerable so I think being skeptical now there doesn't mean that all products are bad for you but but probably the most of most of them are right or there's still not going to do much benefit and there could be unintended consequences everything has trade -offs right when you take some mouthwash right and kill you kill the bacteria in your mouth most of the bacteria they're killing probably are useful right your microbiome you have an oral microbiome a lot of that's good for you right and it may have a short term benefit of maybe making your breath feel a little bit better but but may have a long term cost I don't know I'm not an expert in your life anyway because that's one of the things I looked I thought okay so I've called I don't drink any more but this mouthwash that I'm having is got all this alcohol and I'm throwing in my mouth every day which is killing all the the good but I'm not going to do it.

1:26:18I think they're the dogs in my gut microbiome and also even on our hands we've because of covid we got into this culture of sanitizing all the bugs off our hands and it was quite scary because I think again through this lens of like what is the more natural way to live and this constant sanitizing of our hands and our children's hands and this fear of bugs my girlfriend comes back from the gym and she brushes into the house the others on all this anti -biotic because she's been touching things that other people have been touching when I go to the gym I do that too but yes me Yeah, but look, you've heard of the hygiene hypothesis, right?

1:26:53This is, so we, you know, you have the same immune system. I have the same immune system. As our great, great, great, great, great grandparents, right? I'm immune systems. You know, we all have these, these really amazing immune systems that evolved, protect us from all those germs and worms out there, right? This is something I talk about in the book too. Now, in this highly sanitized world, I still have the same immune system, but now it's like, it's like, it doesn't have anything to do, right? The analogy I use is it's like, it's like a bunch of teenagers hanging out on the corner with nothing to do.

1:27:21It's much more likely to get into trouble, right? And so people who grow up especially in more sanitized environments with dishwashers, without, you know, pets, without animals, etc. are much more likely to develop allergies and various kinds of autoimmune diseases, because their immune systems are no longer busy defending them from the normal pathogens that are out there in the world that we evolved to live in. And now we still have the same immune system. And now, you know, they're like those teenagers on the corner. They have nothing to do. And they're, they increases the probability that they start to attack us.

1:27:56So that's why peanut allergies and various kinds of allergies and milk allergies and whatever, all these allergies are up on the rise, because our immune systems are so unchallenged, they basically end up accidentally attacking us because there's no pathogens to deal with. That's true of a wide range of autoimmune diseases. And so being ultra -stereal environments, we think it's like the great, but actually, and during a pandemic, you know, it can actually prevent you from getting an infectious disease, but it also has costs. And it'll be interesting to see all those kids who were born during the pandemic, who didn't interact with other kids that much, you know, in nursery school or play school or whatever, who were wearing masks all the time, were, you know, getting all those creams, you know, those antibiotic creams, you know, stuff.

1:28:53They might be more likely to get autoimmune diseases. We'll see as they grow up, what happens to them. Daniel, thank you so much. All of your books are absolutely fascinating. It's so bloody annoying because I could just talk to you forever. They're so brilliant. All of the books, absolutely brilliant. And I had so many calls after I last conversation, which I think is almost got 10 million downloads, which is crazy, because it feels like it was a week, a couple of weeks ago, from friends of mine. I got a particularly hilarious call from a lady called Davina McCall, who is, she's been a TV presenter in the UK.

1:29:24She's one of the most famous people on TV in the UK for 25 years. And she called me at 7am, right? And she calls me at 7am. She's, Stephen, I've just listened to the podcast with Daniel, even. She's, I'm running. She's like, get out my way. She's going to be blabbering. And she's running down the street. Well, I'm very honored. Thank you. But I had so many phone calls like that and so many conversations like that, because of that conversation. This book is just a, gosh, the story of the human body. It is essential reading. And as I've heard, it's being used in schools and education institutions.

1:30:01So I do hope that you continue to evolve and update the book with new science as and when it comes. Because it's such an important book. Thank you again for the generosity of giving me your time. It's a huge huge honor. And I say that, I don't say that lightly. We have a closing tradition on this podcast where the last guest leaves a question for the next guest. You know the tradition. Okay.

1:30:20Ah. The question left for you is, for what would you be willing to die today?

1:30:32That's her. Very hard one. I mean, obviously, you know, it's a, it's a, I think we all think about that occasionally, right? I would, if it need be, I think for the people I really love and care about, right? For my, my daughter, my wife. And I think I would, I would certainly be willing to a risk dying, you know, if it really had an enormous benefit for, for human kind. It would not be an easy decision to make. And I've never been put into that position. So it's all theoretical. I think you wouldn't know the answer until you had to make that decision at the moment. Would you die for an idea? I don't think so.

1:31:19But I don't know. Interesting. But ideas can be powerful and important. Daniel Patrick. That's a tough one. It's really tough. And I'm just going to give it away a little bit here. But this is one part of what we were discussing with the previous guests that was on the show. And he asked me this question. He asked me what I would die for and what I'd die for an idea, etc. And so I said I'd die for my siblings and my partner, my romantic partner. For some reason, I said I wouldn't die for my parents, but I think it's purely because, I think it makes more sense for me to reproduce. And I have all the kids I'm going to have.

1:31:56And he asked if I would die for an idea. And as he left, I thought about it more. And if you're saying the idea of a quality or these big ideas that would save lots of people's lives from suffering, I think I would die for an idea. He said would you die for your country as well, which is an interesting one? It depends what the consequence would be if I didn't. One can have these thoughts. You can think about it. The abstract. But it's totally different when you actually confronted with a decision. And what I don't know is whether or not what I just said would actually be the case in the moment.

1:32:35And that's why when he said would you die for your country, I felt like I can't answer that. It would be disrespectful for those that are dying for my country right now. Yeah. But people do. Yeah, and people do. And for me to just sit here in this podcasting chair in this hot studio and go, yeah, of course I would. But I'm absolutely not doing that. Yeah. And if they hadn't, we might not be here today. That's true. Daniel, thank you. My pleasure. Thank you. Do you need a podcast to listen to next? We've discovered that people who liked this episode also tend absolutely love another recent episode we've done.

1:33:09So I've linked that episode in the description below. I know you'll enjoy it.

1:33:23Q1 is often when businesses start implementing new systems and processes in hopes of creating efficiencies for the year ahead. And over the course of my career, I've learnt just how crucial having the right systems in places, one which has helped me across many of my investments is NetSuite. They're also a sponsor of this podcast. NetSuite is the number one cloud financial system through their streamlined platform. You'll find all of your accounting financial management inventory and HR in one place. Their technology has been a real game changer, especially for my team at Flight Studio. As over the last year, we've moved out of startup mode and into scale at mode.

1:33:58We no longer have to juggle multiple systems and having everything together has reduced the number of manual tasks and errors. Over 41 ,000 businesses have chosen to future -proof their business with NetSuite. So if you'd like to learn how it can help your business, head to netsuite .com slash Bartlett and free download the CFO's guide to AI and machine learning. That's netsuite .com slash Bartlett.