Harvard Professor: REVEALING The 7 Big LIES About Exercise, Sleep, Running, Cancer & Sugar!!!

A lot of people exercise because they believe it will help them to lose fat. One of the biggest debates on the planet. What advice have you got for me? So, this is not a well-known fact, but Daniel Lieberman, he studies and teaches how humans are supposed to live. Author and professor at Harvard University exercise disease sleep, nutrition He has the answers on all of those things that most of us care about. We evolved to be very physically active, working in the fields, hunting, gathering, but now we live in a world where only 50% of Americans ever exercise. And the rest of the world is headed our way. cancers depression, anxiety can attribute that to less physical activity. In fact, women who get 150 minutes of physical activity a week have a 30 to 50% lower breast cancer risks. And it's crazy, right? Problem is that we spend 3% of our medical budget on prevention. And yet 75% of the time the disease is a preventable disease. It's a completely backward, stupid system. When you started writing this book about exercise, was there any instant changes that you implemented into your own life? strength training The more I study the importance of doing weights, especially as you age, the more I started kicking myself for being lazy about that. When people retire, they become less active. They tend to lose muscle, and then that starts off a vicious cycle. So, would you say we shouldn't retire? Well, it's a very modern Western concept, and yes, we do pay a price for it. So, how does one go from having a negative opinion towards exercise to becoming an exerciser? As an evolutionary biologist, there are multiple ways of doing that. So, Daniel, what are some of the biggest myths within exercise? Gosh, there are so many. One of the most common, of course, is Daniel Lieberman, he's been to every corner of the world visiting native tribes to understand how humans are supposed to live. And now he has the answers on all of those things that most of us care about on sleep, nutrition, exercise, disease. You know, on disease, he says that 74% of them can be prevented. And he knows how to prevent them. Aging, running, are we born to run? He tells me this story of a CEO that forces his employees to exercise and the impact that that's had on that company. And he talks about how as humans, we've evolved to either use it or lose it. So, maybe maybe retirement is a really bad idea for many of us. One of the most thought-provoking, pivotal conversations I've had on the show. You're really going to take a lot from this one. And I suspect after listening you'll probably start running, too. For exercise or from some of the decisions you've spent your life making. Daniel, your work is so so incredibly impressive reaches such an incredible depth charters new territory and it's been an unbelievable clearly very passion-driven career you had. So, my first question for you is, why are you doing this? Um it's a good question. Um I am you know, I started off being obsessed by human evolution. I ever since I was a kid, I was really interested in human evolution, and for I spent much of my early career working on skulls and heads and why they are the way they are. And then I kind of got involved in public health and issues of health and disease kind of through the back door. I sort of slowly shifted my research trajectory towards studying the evolution of running and then the evolution of physical activity and its relationship to health and disease, and and I've become part of a movement that's often known as evolutionary medicine, which is how to apply evolutionary theory and data to issues of health and disease. Evolutionary medicine, I've never heard that term before, but I love it. Where has your work on evolutionary medicine, let's call it, where has that taken you? Where where has it taken you to learn, to research, to study? You know, so much of what we think about in terms of health and disease comes from a tiny fragment of the world's population. Almost entirely, like 90% of all the medical information comes from people from the United States Canada Europe and Australia. So, in order to to study how bodies really work and how our bodies evolved to be you have to leave uh places like Boston, where I live and go to places like Africa or Mexico or wherever to look at at at other populations and look at how those populations are transitioning to to lifestyles like mine. And so, uh we've been working in Kenya um for the last 15 years or so, um and I've traveled some other parts of the world as well, India you know, to kind of collect some data, but uh but mostly in mostly in Africa. After doing all of this work and after taking in all of this information, how has it shifted your perspective on running, exercise more broadly? What Have there been any sort of significant cognitive perception changes, you know, Yeah, um I actually had a I mean, it doesn't happen very often, but I had kind of an epiphany moment um when I was working in Mexico. We were collecting data on the Tarahumara, very also famous for their long-distance running. And uh there was this elderly guy, he's about 70-something years old, and he's famous for his distance running, and I was asking him how he trained, and I had asked this question of a whole bunch of other people, and the translator I was working with was always struggling to ask that question, because it turns out there's no word for training in in that language. The concept of training doesn't exist. So, so so she was trying to explain to this guy what my question was. Um and I could even with a translator, I could figure out just from his tone of voice, he was like, why would anybody run if you didn't have to? And I suddenly realized, yeah, of course, exercise is a very weird thing, right? If you're if you're a farmer and you're working super hard every day in the fields without machines and whatever, or if you're a hunter-gatherer and you're walking, you know, you know, 5 to 10 miles a day and digging and throwing, you know, doing all kinds of hard work, and you're barely getting enough enough food why on earth would you go for a needless 5-mile run in the morning? I mean, it's crazy, right? The most viewed videos of yours and the most viewed moments in those videos address one question. Do you Do you have any idea what it might be? No, actually. The biggest myths in exercise. Right. And I think you actually pointed out one there with the um insight you got in Mexico. The way we exercise, going to gyms, practicing, is the natural or human, but evidently it's it's a consequence of the privilege of our lives and the comfort we have of not having to seek out our our dinner every day. What are some of the other biggest um myths with within exercise that um you've come across in writing this book? Gosh, there are so many. I had to actually limit limit it to 10. So, I think um if you want to understand physical activity and exercise, you also have to understand inactivity. And I think one of the biggest myths out there is that you need 8 hours of sleep a night. Um and that sitting is the new smoking, you know, that that basically And I if you if you think about those two different myths uh why is it that we're constantly told to sleep more and to sit less? Actually, it's kind of seems a little contradictory to me, right? And it turns out that um uh that let's take sitting first. So, um you know, there are all these uh you know, these slogans like sitting is the new smoking, and it's really bad for you, and you know, every time you sit in your chair, you lose 2 hours of your life, and you whatever. Uh turns out that um all animals sit, right? My dog sits, um cows sit, chickens sit, every animal sits. And hunter-gatherers also sit. In fact, if you uh some of my students actually put sensors on hunter-gatherers, and uh when when we're doing some research in farmers as well. But they sit just as much as Westerners. Um uh so, sitting is there's nothing special about being uh about today's life. It's sitting It's It's that we sit all day long and don't do anything when we're not sitting, right? So, if you uh and furthermore, the the big distance difference is not so much how much we sit, but how how we sit. So, turns out that people who um if you get up every once in a while, right? Interrupted sitting is actually much more healthy than non-interrupted sitting for the same amount of time. So, in other words, two people might In in the West, people sit for an average about 40 minutes at a at about. Whereas hunter-gatherers, for example, or farmers in Africa, where we work get up every about 10, 15 minutes. And when you do that, you actually it's like turning on the engine of your car. You don't even drive it around the block. You're you're you're you're um you're turning on all kinds of cellular mechanisms. You lower blood sugar levels. You You all kinds of genes get activated. And it turns out that that is by far the most important um uh way to way to sit. So, just get up every once in a while. Just pee frequently, make a cup of tea, you know, pet your dog. Whatever. Thinking when I'm on planes and I've got a long flight, I just I always sit in the aisle, right? So, I can get up a lot. Always. Ah. And um What about sleep, then? So, sleep is another interesting one. So, this idea that, you know, um that you need 8 hours of sleep has been around for a long time. It's been around basically since the Industrial Revolution. Um but um if you actually So, so, colleagues in my field, so in evolutionary medicine, have put sensors on people who don't have have all the things that we're told have destroyed sleep. it. We're told that TV and lights and and uh you know, our phones and all these things are are preventing us from sleeping, you know, Edison destroyed sleep, right? Uh so, so, when you put sensors on people who don't have any electricity, they don't have TVs, and they don't have phones, and they don't have have have any of these gadgetry, right? Electric They turns out they sleep like 6 to 7 hours a night. Um and um they uh they don't nap. Um so, this idea that natural human beings sleep 8 hours a night is just is just nonsense. It's just not true. And furthermore, when you start looking at the data 7 hours, if you actually look at if you graph sort of how many hours a night you sleep on the x-axis and sort of uh you know, some outcome like cardiovascular disease or just how how likely you are to die it's kind of a U-shaped curve. So, people who don't get much sleep are are in trouble. Um but the bottom of that curve is pretty much always about 7 hours. So, people actually do better if they sleep 7 hours rather than 8 hours. And yet we're told that if you don't sleep 8 hours, there's something wrong, right? Oh, so you can oversleep. Well, yeah. I mean there's also some complexity to this, too, because of course people who are ill might be sleeping more. And so there's some there's some biases that creep into the how you analyze the data. But but basically it turns out that seven is for most people optimal, but there's a lot of variation, right? Never You know, teenagers sleep more, older people sleep less. It's complicated. One of the things that popular in culture as well as this idea of doing 10,000 steps a day. Yeah, now that's fun. You know, that started because of a Japanese pedometer pedometer. Um so but right before the the Olympics were in Tokyo in the in the '60s, uh they had invented the pedometer and they were in sitting in a boardroom and they were discussing what to call the pedometer and they picked out of just out of the blue they picked 10,000 steps because that's apparently an auspicious number. And it sounded about right. There was no science behind it. Interestingly, it turns out it's pretty good. Um if you actually if you look at at steps per day and health outcomes, um your average hunter-gatherer um walks between 10 to 18,000 steps. Depends on male, female, etc. And and if you look at steps per day and and outcomes, um um at around 7 to 8,000 steps the curve kind of bottoms out, right? There's doesn't seem to be a huge advantage to taking more than that per day in terms of you know, large epidemiological studies. So, turns out to be not that bad a goal, but it's not a there's no it's not a perfect number like a lot of things, right? It's just a kind of a it's a reasonable it's a reasonable goal to shoot for. When you um when you started writing this this book about exercise and running and all these subject matters, was there any instant changes or any real lasting changes that you implemented into your own life from everything you'd learned? I I think about that all the time with this podcast. I'll have a guest on. I have these many eureka and then something will stick. So I'm I'm wondering having studied all all of these people all around the world and looked at their bodies and exercise and physical exertion, what have you taken into your own life that has stuck? I would say that I've become more serious about doing some strength training. You know, I've I've always loved walking and running and you know, endurance kinds of activities and I've always sort of hated doing weights, you know. I just don't like it. And I'm I'm I'm I'm a wimp, you know. I'm not a very well I'm I'm not a very strong person. And you know, people tend to do what they like, right? You get reinforcement from it. And uh the more I study the importance of resistance training and the more I study the importance of doing weights, especially as you age, um the more I've uh the more I I started kicking myself for for being a being lazy about that. So now I try to do a good two strength workouts out of every week at least. And uh and take it more seriously because especially as you age, loss of muscle mass can be really debilitating. There's a um the technical term for that is sarcopenia. Sarco is is the Greek word for muscle and penia is loss, so muscle loss. So as people get older, they tend to lose muscle and when you do that, you become frail and you lose functional capacity and then that starts off a vicious cycle, right? Once that happens, then you're less likely to be physically active and then of course when you're less physically active, your muscles begin to waste away more and uh it's very debilitating. So I think as we get older and I'm getting older, it's more and more important, you know, to to kind of incorporate that. So I think that's the one thing that I've I've taken to heart. Yeah, from what you said there, it sounds like not doing resistance training, not doing not lifting weights as you age almost accelerates aging and in any sort of superficial sense, but but it also in a physiological sense, you're you're increasing the speed of aging. Yeah, I'm not sure if I'd think about it that way, but it I think I I kind of reverse it slightly, which is that you know, aging is just the clock ticking on, right? There's nothing we can do about age, but senescence is the way the way our bodies degrade as we get older. And what physical activity does, perhaps maybe the most important thing about physical activity, is that it slows senescence, especially for certain organs and systems. And there are different kinds of physical activities. So there's endurance physical activities, you know, like running, walking, etc., swimming. And then strength or resistance physical activities and they have different kinds of ways in which they slow various properties of senescence, which we, you know, colloquially call aging. And all of them are important. And I think one of the things that's really interesting about humans, in fact, I think it may be the most important thing about this book and you asked about myths earlier. The most important myth, I think, by far, is this idea that as you get older, it's normal to be less active. And that is just not true. Um we evolved to be grandparents. We evolved to live with one thing that's most interesting about humans, maybe, is that we evolved to live about 20 years or so after we stop reproducing. No other animal does that except except orcas, maybe killer whales. But with the exception of killer whales, humans have this really weird life history. We we we evolved to be grandparents. But grandparents in the old days weren't, you know, retiring to Florida or I don't know what they what they do in England or whatever, go to Mallorca or whatever and you know, kick up their heels and play golf or whatever with carts. Grandparents in the in the olden days, right? Or in in many cultures still today, are working, right? They're working in the fields, they're hunting, they're gathering, they're getting food for their children and their grandchildren, they're helping with child care. And that physical activity is, you know, that's what their job is, to be physically active. But in turn, that physical activity turns on an amazing suite of of of physiological processes that counter aging. Turns on repair and maintenance processes that not only keep our muscles strong, but also keep our DNA from accruing mutations, keep our mitochondria numbers high, keep um keep our the cells in our brain from accumulating gunk uh so that prevents Alzheimer's and other forms of dementia. I mean, for almost for every system of the body, physical activity has has benefits that slow the aging process. And so when you stop doing it, you accelerate and that's the way in which you it you perceive it as accelerating aging. But really it's the absence of physical activity, which lets aging run amok. In your first book in 2013, The Story of the Human Body, in chapter 12 you said um you used this phrase, you use it or lose it, basically. We we evolved to use or lose our bodies. And I was sat with um someone recently and I was trying to figure out why it appears that when people retire or the other instance I've seen is when their their elderly partner passes away, it appears as if they don't live much longer. Yeah, it's kind of like kind of folklore or something that once you retire, your days are kind of numbered. Yeah. Yeah. And I I was trying to figure out the evolutionary reason for that, but it sounds like that's kind of what you've explained there. Well, I mean, I think part of that is um is is depression, right? Um um when you lose a partner, I mean, grief and depression, your cortisol levels go up, your immune system goes down. I mean, you know, it's it's it's really tough on your body. I mean, psychosocial stress plays a serious physiological toll. But but also, as you just pointed out, when people retire, they become less active. And that that loss of activity has enormous effects on every aspect of our our our of our of our body. I mean, and our brain and our minds. I mean, physical activity is important not just for physical health, but also vital for mental health. And um I think a lot of the problems that uh a lot of mental health issues we have today, depression, anxiety, uh some of them, you know, to some extent, uh we can attribute that to loss to less physical activity. And as people age, becoming less physically active, again, makes them much more vulnerable to a wide suite of diseases. So would you say we shouldn't retire? Well, or if you do retire, I mean, retiring is a again, another modern weird thing, right? Nobody retired in the past. I mean, if you're a farmer, it's like a subsistence farmer in name it, any place, right? It's not like suddenly you hit 65 and all of a sudden, you no longer have to work in the fields. You work in the fields until you're, you know, until you're dead, right? And hunter-gatherers don't retire. They they continue to be physically active until until they die, right? Or until they get too sick. So it's a very modern Western concept um and um and yes, we do pay a price for it. But you of course can replace, you know, work that you do with with with challenging, rewarding, fun things to do. The important thing is just not to not to stop being physically active. One of my favorite studies ever published, without a doubt, um is is a is a study done by a guy named Ralph Paffenbarger. He realized that uh places like Harvard are fantastic for studying aging because um Harvard, like other private universities, never lets go of their alumni. So, until you the day you die, they're asking you for money on a regular basis. And and so they're um um and so he he got the alumni association, the Harvard Development Office, to let him follow a series of Harvard alumni from several years and keep asking them in questions about their physical activity levels and also their diet and whether they smoked and stuff like that. And then he tracked them for 25, 30 years. And what he found was that the alumni, we after corrected for every factor you could think of, that as you as the alumni got older, the effect of physical activity on their health outcomes was bigger and bigger. So, alumni who were in their 20s, 30s, and 40s, for example, who were were exercising four, five times a week, they had about 20% lower death rates. By the time they they got to their 60s and 70s, the alumni who were exercising more had 50% lower death rates. So as you get older, so what and this has been replicated again many times, but what he showed was that as you get older, exercise becomes more, not less, important for maintaining your health. Been thinking a lot about this cuz I was I was saying to Jack, my dad is 60-ish, but he's very, very out of shape. Very, very out of shape. And I was in um I was in Indonesia and I was with my girlfriend and we went and we were going white water water rafting. So, we had to go down this really big hill. And with all these stairs, it was like 300 m of stairs. And I remember of just thinking, my my dad wouldn't be able to do this at his age at 60. And I want to be able to go down those stairs when I'm his age because at the bottom of there was a fun activity with someone I loved. And to think that I'll get to a point in my life where not so far away in the grand scheme of things um where I won't be able to go up or down some stairs because I'm 60 um because of my sort of genetic predisposition as I saw it was quite was quite sad. But having heard you say that, it's really feels much more like a choice than it is genetics. Yeah, well, we have this expression in my field, which is that genes load the gun and environment pulls the trigger, right? Some of us have genetic predispositions towards being, you know, more likely to get diabetes or heart disease or this or that or the other. But our great, great, great grandparents in different environments weren't getting these diseases or they were getting them at much, much, much lower frequencies. It's not because they were dying earlier. It's because these diseases were more less common. So I think we too often blame our genes for uh many of these these these diseases um or many of these health problems. Um and it's I'm not in any way denying the role of genetics is but that environment is way more important and we have control over our environment to some extent. And so if you want to reduce your risk of cardiovascular disease, reduce your risk of diabetes, reduce your risk of Alzheimer's, dementia you you exercise isn't a magic bullet. It's not going to prevent you from getting those diseases completely, but it lowers your risk uh quite, quite, quite substantially. And we know why, too. I mean, we have an immense amount of data on why that's the case. Um uh for every single one of these diseases, we understand the mechanisms by which physical activity has uh you know, important mechanistic effects on on these diseases. So, it's there's epidemiological data, there's mechanistic data, there's personal data. The problem is that it's hard to do, right? It's it takes willpower to um overcome the the the the inertia of of of of doing what's completely normal, which is wanting to take it easy, right? I was I was just, you know, I just flew yesterday from Denver to Boston. And in the and the in the in the airport you know, there are these escalators right next to the stairway, right? Mhm. And and and and um the escalator and the stair it wasn't a huge stair. Everybody's lining up to take the escalator. And like the stairs are totally free. So, I being me, I of course I can't I'm not allowed to take the escalator unless, you know, I have to, right? So, I I ran up the stairs, but you know, it's but those people taking the escalators, nothing wrong with them. There's they're not lazy. It's just an instinct, right? It's an instinct to take to take it easy when you can, right? Because when and we now live in a world where everybody can do that, right? Because we have escalators and and lifts and cars and shopping carts and all these wonderful devices to make our lives easier. And now you have to overcome this fundamental basic instinct to take it easy in order to be physically active. And that's basically what exercise is. And so and and furthermore, if you're out of if you're unfit and you're not really, you know, exercising isn't any fun, right? It's it's it's it's unpleasant. You, you know, you sweat, you get hot, and you get cranky, and you know, um and and it's not that rewarding uh until you get fit. And so uh people hate it, right? Um and and then we blame them for being lazy. But they're actually just being they're just being normal. And I think we need to have more compassion towards towards people who struggle to exercise. Quick one before we get back to this episode, just give me 30 seconds of your time. Two things I wanted to say. The first thing is a huge thank you for listening and tuning into the show week after week. Means the world to all of us and this really is a dream that we absolutely never had and couldn't have imagined getting to this place. But secondly, it's a dream where we feel like we're only just getting started. And if you enjoy what we do here, please join the 24% of people who watch this channel regularly and have hit that subscribe button. Means more than I can say. And if you hit that subscribe button, here's a promise I'm going to make to you. I'm going to do everything in my power to make this show as good as I can now and into the future. We're going to deliver the guests that you want me to speak to and we're going to continue to keep doing all of the things you love about this show. Thank you. Thank you so much. Back to the episode. This basic instinct to take it easy are we evolved to be lazy take escalator riders? Well, I wouldn't use the word lazy, but we are evolved to take it easy, to to rest whenever possible, right? So, we've now got ourselves into a bit of a comfort crisis here because everything has in our lives is optimizing us for convenience and ease. Right, right. And well, it's also it's it sells, right? I mean, comfort I mean I mean, who prefers to sit in economy as opposed to business class, right? Nobody, right? Comfort's nice, right? Who prefers shoes that are uncomfortable, right? We we we, you know, comfort's comfort's, you know, we we love comfort, right? But since when is comfort necessarily better for you, right? I mean, are comfortable shoes actually better for you than going barefoot or the comfortable chair is better for you than or taking the the lift better for you than taking the stairs? the short term or at least it appears to be today. Right. Yes, because we often value the short-term benefit over the long-term cost, right? Um that's, you know, hyperbolic discounting is the technical term for that. But but um so we, you know, we live in a world where where we we we, you know, we pay extra for for comfort or we and we'll we'll prefer it. But um but now we also live in a world where we have to now go out of our way to be physically active because it's no longer necessary. And so again, I'll go back to my original statement, which is that people evolved to be physically active for two reasons and two reasons only. When it's necessary or rewarding. When we don't make it necessary, we need to figure out ways to make it rewarding. And and that's hard. It's very hard. Making it rewarding. So, one way that you might make something rewarding is by looking at the stick. And then the other side is maybe the carrot. But just looking at the stick then, you were going through a series of diseases a second ago, Alzheimer's, um high blood pressure, all of these kinds of things, cardiovascular diseases. I almost think we've come to assume that these are inevitabilities of life. Yeah. We'll get cancer. Yeah. One of us will get Yeah. Someone in here is going to get Alzheimer's. And that's the way we live. So, we're we're we're preparing to medicate when that day comes. That's right. I get God forbid diagnosed with something. That's absolutely right. In fact, that's what medical students today are taught, right? If you go to medical school today you're taught that as people get older, their blood pressure goes up. I can tell you that's just not true. It's in the Western world where people are physically inactive and eat crap diets that their blood pressure tends to go up. But there are plenty of people I'm actually one of them, right? Who don't have high blood pressure as they age. And guess what's the best way to prevent getting high blood pressure as you age? It's um you know, I sound like a broken record, but we have this idea that as you get older, yes, you're going to you're and we're lucky, right? You know, because we don't die from smallpox when we're 30. We're lucky to get cancer when we're 60, right? What we've done is we've confused diseases that are more common with aging with age being a cause of those diseases in the first place. And they're not inevitable inevitable diseases. Um and many of them are preventable. And and the problem is that in our society we we don't value prevention very much. We we may talk about it, but we don't really put our money where our mouth is, right? In the US, which is arguably one of the worst health care systems is the worst health care system among the industrialized Western world. We spend approximately 3% of our budget our medical budget on prevention. And yet when people walk into a doctor's office, 75% of the time the disease is according to the Center for Disease Control a preventable disease. So, we essentially spend nothing to prevent diseases that overwhelm our system and cause enormous amounts of misery. It's a completely backward, stupid system. And so and and the good news is it's not that hard to prevent a lot of these things. Um um it takes willpower and um takes education and it takes access to to good quality food and whatever. Um but um uh so in in one sense, it's very depressing. On the other hand, the optimist in me says, you know, we really can do something. And people even if without even if they're not wealthy or whatever, I mean, there are simple things that everybody can do to improve their health outcomes. These diseases we we encounter today as we age and just generally in our society, when you look at hunter-gatherer hunter-gatherer communities or you look at certain tribes around the world, maybe in Africa do you see the same um the same types of diseases in the same um occurrence level of occurrence? Or is there some diseases which just don't like I'm wondering if like if cuz you know, cancer seems to be so popular for as as disease and Alzheimer's and these kinds of things. So, I wonder, has that always been the case throughout human history? And is that the case in other parts of the world? Uh such a good question. So, first of all, some of these some of these diseases are really hard to to measure in non-Western populations because we don't have the diagnostic tools. So, nobody really knows how common cancer is in in in a lot of parts of the world, right? There's just no the data don't exist. That said, when you make estimates and you do look at the studies that are out there and even if you look in in in historical records in in places like Europe where people have been keeping track of this, there's no question that cancer rates have been rising and that cancer rates are much, much more common in the Western world. There's a strong association between cancer and wealth. And that's because cancer is basically a disease of energy, right? When your cells cuz cancer is basically natural selection gone awry in the body. It's when cells start competing with each other um in ways that that cause it basically and and start, you know, going, you know, multiplying and dividing out of control, right? It's a kind of natural selection. And what is it that those cells are doing? They're competing for energy. And when you have more energy like when you're eating more and being less physically active you can you basically feed those cells. So, um so cancer so a high levels of insulin insulin is highly uh related to to cancer. High insulin levels are are carcinogenic. Um high levels of of body of of energy you cause women for example to increase the the amount of estrogen and progesterone that they produce. Men produce more testosterone. These are and these are these are hormones that um of course are for good for reproduction, but they're but again, we have we evolved to be to have as many babies as possible, right? But that doesn't mean that translates into health, right? So, more estrogen, more progesterone increases risks of say breast cancer. More testosterone increases the risk of prostate cancer. So, if you look at most diseases, right? People are more physically active, they have lower levels of estrogen, progesterone, testosterone. They have lower levels of insulin. They have lower levels of blood sugar. All of these depress cancer rates. And on average, people who are physically active have much lower rates of almost every single kind of cancer that you can think of. Women who walk 150, you know, get 150 minutes of physical activity a week have on average about 30 to 50% lower lifetime breast cancer risks than people who are sedentary. And yet for some reason, this is not a well-known fact. Um and we under we have we have epidemiological data. We have mechanistic data. We understand how and why it works. And yet and yet how often do you hear about cancer prevention? We talk about treating cancer, which is all important. If I get cancer, I would like it treated, too. Thank you very much. But why don't we spend more energy and activity and and and have more education about how to prevent cancers in the first place? Physical act I mean I've never had that before. So, that's that's really helped me um to add more value to exercise in my mind. You're talking there about insulin levels and how that has there's a link between your insulin levels and your chances of getting cancer. Sugar. Glucose. Inflammation. Bad. Yeah, I mean I mean look, if you want to you want to take like the three things you should, you know, if you really care about your health, don't smoke, right? That's kind of obvious. I think everybody knows that. Get some exercise. I don't think you need me to tell you that, right? And and cut down on sugar and foods that are high in sugar and low in fiber, right? That you know, what we call high glycemic foods. Those are the foods that elevate your your your your blood glucose levels. Your your insulin levels shoot up. And insulin insulin, the basic function of insulin is is is it's it's what we call an anab- anabolic hormone. It's its job is to is to store energy. Glucose. Glucose, but also fat. Okay. All right. Okay. So, ins- ins- what insulin does is to get energy into cells. So, it's like a taxi. It's like an Uber. It's like a taxi, yeah. Well, I mean it it's not a tac- it's like a it's telling other cells to do that. So, insulin for example binds to other cells that are the actual taxis. So, it's like it's like calling the Uber, I would say maybe, right? Um and um and insulin is is, you know, it's the funda- So, when you when you eat food, insulin levels go up because its job is to store that energy. And when you exercise, insulin levels go down because because you want to then use that energy, right? So so uh so when cells get more energy, they're more prone to going out of control, basically. And and and and inflammation is caused by basically by getting you store so much fat in your cells that those fat cells start to swell. And when those start to swell, like anything, right? They start to rupture. They get damaged. And that damage attracts the immune system and the immune system gets turned on and that causes inflammation. So, so too much adiposity, too much fat, you know, overswollen fat cells is the is a primary cause of systemic inflammation. And inflammation is like the slow burn in our bodies that causes widespread damage to pretty much everything you can think of. And it turns out that So, the two ways to deal with inflammation are one to prevent it, right? So, don't eat foods that are pro-inflammatory. Like? Anything with a lot of sugar, basically, right? That I mean that you know, the sugar is highly inflammatory. Um or trans fats are highly inflammatory. But also, turns out many people don't know this, but you also want to turn down your immune system, right? You want to turn the dial down. And I don't know, I'll just give you one guess what it is that does that. Exercise. Exercise. And the and and and the way it does that is that when you when you're physically active, you're using your muscle cells. It turns out muscles are also an endocrine organ. Your muscles are producing a molecule called interleukin-6, IL-6 that in low levels is pro-inflammatory, but at high levels, it's actually anti-inflammatory. It turns down inflammation. And your muscles because a third of your body is muscle, right? When you go for a run or or swim or bike ride or whatever you're producing a ton of this stuff and it turns down levels of inflammation. So, people who are physically active, even if they're overweight are actually controlling and regulating their inflammation. And we never evolved to regulate inflammation because in this way because we never evolved to be physically inactive. Until recently, nobody was physically inactive until they unless they were dying, right? So, so we never evolved an alternative mechanism to regulate inflammation other than physical activity. And we didn't live in a world with this much sugar. We never lived in a I mean, it's astonishing. You you pay more money for foods today that have less sugar added. Right? I mean, that's just ridiculous, right? Cuz it's so cheap. And sugar is you know, we love everybody loves sugar. I mean, I've um I've gone hunting with um hunter-gatherers, you know, you know, foraging hunter-gatherers. And um and I can tell you that they're honey addicts, right? I mean, I've gone out with these guys and they go from you know, if if they if they fail in their hunt like by 10 or 11, if you haven't killed an animal, you know, that's it for the day, right? And then it come it turns from being a hunting expedition to a honey collecting expedition. And they'll go from hive to hive to hive get smoke, burn out the bees and just gorge themselves on more honey than I could possibly imagine to eat. Except these are lean physically active hunter-gatherers and they they handle it just fine. Um but it's you know, it's the it's the Paleolithic equivalent of, you know, eating Mars bars all day long. But they've been out doing physical activity for how long? Yeah, I mean, the average day is about 15 km of of walking with some running, you know. So, so so they're you know, they can they can they can cope with it. How many hours is that? Oh, that's two to three hours, probably. Okay, so from that I have garnered that I need to do 15 km a day for two to three hours every day. Well, remember, it's not a prescription, right? So, that's that kind of like the paleo fantasy sort of naturalistic fantasy that if you live like a hunter-gatherer, somehow your your your world will be perfect, right? That's basically what the paleo diet is sort of all about, right? And that's not true, either. Yes, you need to be physically active, but it turns out that a certain amount you know, if you're any any physical activity is better than none, right? And if you look at the kind of any curve of any output, any health health health health outcome like how many years you live or whether you're likely to get cancer or heart disease or whatever, you know, any little physical activity, your curve starts to fall quickly, right? Your your likelihood of cardiovascular disease starts Just, you know, a few minutes a day of exercise has big benefits. But eventually that curve flattens out, right? And it flattens out well before the hunter-gatherer level. So, you don't need to be a hunter-gatherer in terms of physical activity to get the benefits. This is a I've asked a few people this question. I don't think everyone's anyone's really answered it. Um but I suspect you might be able to. If if you were responsible for redesigning the nature of our modern world to make it more matched and less mismatched what are some of the first things you would do to help society benefit in terms of our happiness and our health? I I think about this all the time. I think cuz we we we don't seem to be turning around. We seem to be hurtling in a direction kind of unconsciously towards artificial intelligence and moving less and being more sed- sedentary and taking pills more to fix everything. Lonelier than ever before. And I got you know, if we were to redesign it, blank canvas piece of paper It's a tough question because um we've essentially given ourselves what we want. Right? Um I can go into a supermarket and I mean, I can do something that's unimaginable until recently. I can have I can I can have basically anything I I can eat better than the king of France, you know, a few generations ago. I can I I can I mean, here we're I can New York I there's like every cuisine possibly available to me. I I don't ever have to climb the stairs. I can take elevators. I mean, we've we've we've we've made our world so convenient and comfortable um and yet there are consequences to the many of the things that we crave and want. So in a ideal world, you don't want to you don't want to rem- I mean, you have to you have to honor and respect people's um um desires, right? I'm not a I I don't believe in in in preventing people from taking the elevator, right? Or or forcing them to you know eat eat whole grain bread as opposed to white bread, right? But if you banned white bread and you banned elevators other than for those people that need it for accessibility reasons, etc. They would do better. Over the long term, they would be healthier and happier. They would. Right. So, the it's really a a balancing act between between um um respecting people's liberties and choices and educating them and helping them. So, in my world, I would I would do more to nudge people, right? Um I would instead of banning sugar, I would tax it more. Um instead of um uh pushing uh all kinds of foods on people, I would push I mean, why don't we why don't we advertise healthy foods the way we advertise unhealthy foods, right? I mean, when's the last time you saw an ad for just how amazingly healthy asparagus was, right? But that doesn't get the part of my brain going, does it? No, it doesn't, but um but we could do more to to nudge and encourage and help people, right? You don't have to like ban sugar and cookies, right? Uh the way some people but but but simply promote um and help people help themselves, right? Most people want to eat healthier food. Most people want to exercise. Um but they live in a world where it's hard to do it and they live in a world where um there are very few incentives. I would make it such that healthy food would be as as inexpensive as as unhealthy food. And make sure that that people had incentives and and make it also fun to be physically active. Like for example, um every I mean, who doesn't like to dance, right? Every culture in the world has dancing, right? Dancing is a form of of of physical activity. It's social, it's fun, it's engaging. Why don't we have uh have Why doesn't every every town in America sponsor dancing? Right? Um you know, it would probably do an enormous amount for people's physical health and their mental health. I mean, we could do that I mean, that's just one example, right? So, I would I would um I would I would I would and and why is it that uh in medical schools doctors don't learn about I mean, they don't they don't study nutrition and they don't don't study exercise and they don't learn um because that's because in our medical system is designed to treat people after they get sick rather than prevent people from getting sick. So, so we need to we you know, reverse how we fund health care, right? And so, schools of public health are these kind of little marginalized places where you know, where where great ideas go to die, right? And and medical schools where all the money is, right? And doctors aren't taught to to deal to to to I mean, there are entire fields of medicine that don't have the word preventive associated with them. I mean, have you ever heard of preventive orthodontics or preventive you know, optometry or preventive you know, the preventive orthopedics. I mean, it just doesn't exist, right? So, we we could do a lot more um and and have enormous benefits. Chapter 11 of this book, you talk about someone who has taken their own approach to getting people moving and exercising um in their own business. That was the Björn Borg company. I love that. Björn Borg company. Can you tell me about that that company? Yeah, so I was um so I was I was curious about this idea of how to get how to help people be more physically active, right? And again, you know, my my fundamental hypothesis is that we evolved to be physically active either when it's necessary or rewarding. And so, I was curious if there was any any companies in the world that have made physical activity necessary. In other words, what if we force people to be physically active? And I found one so far. I think there's only one company in the world that I know of. Maybe there's some others, but this is the only one I've ever found so far. And it's the Björn Borg sports company in Sweden where the CEO of the company is this crazy sort of exercise addict and he um he requires every member of the company to to exercise. They have sports hour every Friday at 11:00 o'clock. So, I actually um when I when I was like searching around and I was thinking, you know, I like working on the book, I actually, you know, I got I I thought I found a an article about them and I, you know, I clicked on the on the company website. And you know how most companies have a little contact us? Mhm. So, I I clicked on the contact us and I wrote a little note saying, you know, "Dear Björn Borg company, I'm a I'm a researcher and evolutionary biologist. I'm interested in exercise and I'm and I'm fascinated by how your company um requires people to exercise. Can I learn more?" And the next morning, there was a an email from the CEO of the company saying, "Why don't you come and visit us?" So, so I hopped on a plane uh a few a few months later, went to Sweden and they they let me He was so nice. He just let me just go anywhere in the company. And I I went to sports hour and I I talked to to employees throughout the company and it was fascinating. I mean, um a lot of the employees of the company um first of all, a bunch of people apparently left the company when he took over as CEO and required this. But it doesn't matter who you are. You could be working in the mail room, you could be the CEO, you could be on a visiting board member. Whoever you are, if you're there on Friday, you have to go exercise with them. And they have this pretty serious kind of exercise thing. And apparently, some people quit. Um but um but but pretty much everybody else said, "You know, it's actually a pretty damn good thing." Do you agree with that approach? Well, yes and no. Um every university in the world used to require and every school, right? Supposedly requires exercise, right? I'm sure you had physical exercise you know, physical some kind of phys ed required in your school. Those standards are slipping around the world and more and more kids are doing less and less in school. Uh universities were are no exception. It used to be that all universities required some degree of physical education. Uh mine was no exception. In fact, Harvard was a leader in that back in the, you know, 100 something years ago. And over the uh since basically the 1970s, that's basically disappeared. Although most students, if you ask them, they think, "Yeah, it's actually a pretty good idea." So, I don't know. Maybe we can bring back exercise as a And and the thing is that if you get used to it, right? When you're young, you're more likely to do it when you're older, right? Cuz you set Those are the that's the age in which your habits become become well, your habits become your habits, right? And so, at there's a certain age where where if you can keep keep get that making it make it a habit, you're probably more likely to continue doing it for the rest of your life. We kind of see it as overreaching, don't we? I was thinking about if I was to announce one of my companies that everyone is now required to exercise, it would seem like like tremendous overreach. If I announced that everyone is required to read a certain book, they'd do it and it'd be fine. And it might be seen as a positive thing, right? Might be a representation of our values that we are learners and we're innovators and we keep, you know, nourishing our brains. But if you turned around to your team and said, "Listen, we're all required to you're all required to go for a run every day or something." People would it just feels personal. Like that's not the responsibility of an organization to tell me to go exercise. But we have we have company, you know, retreats. I mean, we do all kinds of stuff where people are required to do it. So, I don't know. I challenge you. Try it. What we do and what we've always done, we even do it with this team. The Drive CEO team is about 30 people. So, we have a fitness channel in the company um Slack channel, the communication channel that we use. And in that channel um and we did this at my previous company as well where we would enable and facilitate. So, we we someone started a women's football team. So, we enabled it and promoted it. Someone started a men's football team, so we enabled it and promoted it. And this this also applies to non-physical sort of exercise related clubs like someone starts a reading club and we enabled it and promoted it. Um and we also paid for it. If they need to if they need new kits, for example, when the women's football team needed wanted to have their own uniforms, we paid for it because we saw a huge value in terms of staff retention, connection, community and all those things that actually lead up to staff retention if we could have more social clubs outside of the office. You know, if you're thinking about leaving a job, there's a number of things you weigh up, the pay, the job, whatever. But you also weigh up how the community, like the group of people I love and how much they bring to my life. And I actually think in the remote working world, um it's something that CEOs and leaders have really not paid enough attention to that if they really want to retain their team members, they should have them together as much as they can even outside of the office bonding in a world where screens are on the rise and pubs are on the decline and social activities and churches are on the decline, there's less sort of uh institutions that connect us socially, work has a big opportunity to do to do that. So, one of my big things that's always in my head is like how can I get the team members of my companies to hang out more and and a multiplier to that is how can I get them to hang out more and move their bodies more cuz then they'll feel better. Right. Well, well, think about it. It's play, Play, yeah, exactly. And I mean, and play is what is another thing we evolved to do, right? What kids play and we're one of the few species that plays as adults, right? And what is play? Play is a way in which you you you learn cooperation, you you you build community, um but you also move your body, right? In the first chapter of your book, you say that you went to visit the Native American tribe and I'm going to try and perhaps pronounce this, the Tarahumara. Tarahumara. And they're famous for their long running. Yes. What did you learn about running from them? Well, it's you know, they have been famous for well over 100 years. I mean, many uh people have gone to study the Tarahumara and and have commented on their amazing ability to run. But what I I really learned from them is that um uh for them, physical activity is spiritual. Um you know, there's this book Born to Run that uh that describes their their running and calls them a hidden tribe of super super athletes. They're not hidden and they're not super athletes. Um and um and the one thing that the book missed was that the the main impetus for the for the for the running they do these famous long-distance races is that it's a form of prayer. Um it's really very beautiful. Um and um and it's it's a metaphor for for life and and and it's also an an opportunity to bet and sports and all that. It's all wrapped into one. And and what I've learned was that this actually used to be almost universal among Native American populations, right? Native American tribes. Everybody had long-distance races and ball games and and all they were all had a spiritual element. It's just that they've they've retained their traditions because they're in a very remote part of of Mexico that's essentially inaccessible. We all used to do this. All uh humans used to do this. And in fact, if you think it if you look around the world, every population has this tradition of endurance endurance events. Some of the subject matter you talk about in your book, but also outside of your book is is how we used to run um in terms of, you know, I was at the foot doctor. What's it called? I I don't know what they're called. Orthopedic Podiatrist. That's what I said. Podiatrist. What did I say? But I went to the podiatrist the other day because I I got this What's it called when your in a point out on my foot. This part of my foot here started to get lots of pain. Every Plantar fasciitis. That's it. Plantar fasciitis. I started to get some plantar fasciitis. And it was just this ongoing pain. And they prescribed me some insoles. I stood on a couple of machines, some soft stuff, and they measured my foot and took this scan of it and said, "Right, basically you're standing wrong. Um your arch is a bit too flat. Take these insoles and wear them in all of your shoes." And I just I always think in these moments when someone prescribes me something that's not natural, I go, "Why? Like where did I go wrong?" And I think that's the key question. Where did I go wrong? Who lied to me? To the point now that at 30 years old, I have these bloody insoles that I have to put in all my shoes. Because presumably that's not natural. Presumably my my ancestors don't have bloody insoles. Yeah. So, plantar fasciitis is what I would call a mismatch disease, right? A disease that's more common or more severe because our bodies are inadequately adapted to modern environments. And in your case, and as as is the case with a lot of people, you have a weak foot. So, so we you know, you you look like you go to the gym. Looks like you're pretty fit person, right? I'll make a bet you you strengthen pretty much every muscle group in your body except your feet, right? No comment. Right? Well, but we don't, right? And one of the reasons is because we we encase our feet in stiff-soled shoes that are very comfortable. And and the reason the shoes are comfortable is that your your foot muscles have to do less work when you're you're using those shoes, right? We have shoes that are stiff soles, they have arch supports, right? And your your foot has four layers of muscles in them. And those muscles are supporting your arch. And at the bottom of those four layers of muscles is this layer of connective tissue, the plantar fascia. And the problem with the plantar fascia is that if it stretches too much, it like anything else, right? It gets inflamed. But it's got almost no vascularization, right? So, it has it's very hard for it to repair itself when it gets inflamed. To prevent plantar plantar fasciitis, the best way to preventing it is having a strong foot. A strong foot is a healthy foot. So, the way to way to treat the disease in the long term is to strengthen your foot. But if you want to just alleviate the symptoms, that's what your podiatrist did by giving you an insole, right? It's basically preventing your muscle your arch from collapsing as much, making it more comfortable so your your plantar fascia gets stressed less, and so it can kind of um alleviate that that that that that stretching and hence the pain, right? So, that's a typical example of what I call disevolution. It's what what happens when you treat the symptoms of a mismatch disease rather than their causes or preventing their causes. So, podiatrists are a bit like drug pushers in that sense, right? Because they're they're essentially putting your foot in a cast, right? And then and for the rest of your life, you kind of have to keep using them unless you strengthen your feet. So, I So, So, there's nothing wrong with those, you know, treating the symptoms. I mean, pain is no fun. So, wear the insoles, right? To kind of, you know, alleviate the pain, but also work on strengthening your foot, and I think you'll find that the plantar fasciitis will will disappear and never come back. So, the plantar fasciitis fasciitis um has now healed after about a month of wearing the insole. Um I no longer have the insoles um with me here in New York, and I don't have them in any of my shoes because I've also taken a bit of time off um running on my feet. I was playing a lot of football. So, now I'm at a point where I can go to the preventable stage, prevent it happening again. And you said to strengthen my foot. How does one strengthen their foot? Good question. So, there are some exercises. Um they're kind of foot doming exercises and things like that. But they're they're, you know, I can send you some links to videos showing you some good foot strengthening exercises. So, that's one way to do it. Um but the other way is to wear more minimal shoes. Um to wear shoes that aren't stiff-soled, that don't have arch arch supports. Go barefoot a lot, right? Um and those that will naturally strengthen the muscles in your foot cuz you'll have to use those muscles. So, you ever gone for like a long walk or run on a beach, right? And afterwards, your your feet are kind of tired. Mhm. Right? The reason your feet are tired is because you're now working on a compliant surface, right? It's not stiff. So, your muscles having to work more to stiffen your foot to push you forward, right? Jack, could you go grab my the black shoe out of my bag? I just want to show him something. So, um so, wearing shoes that aren't as stiff-soled when they don't have a arch supports will slowly strengthen your feet. But, and this is a huge but, if you do too much too fast, you will your plantar fasciitis will come roaring back and you'll hate me. You'll like you'll never forgive me because um Yeah, there's a Vivo barefoot. Um yeah, I I wear the same shoes. Oh, you you've got the same shoes on. Um great shoes. Yeah, those are wonderful shoes. Those are those are the those are the exactly the kind of shoes that will help strengthen your feet. These are fairly a new addition in my life. Yeah, they and they feel really strange cuz you can kind of feel the floor. Yeah, it's exactly what you've described is Yeah. But but you you can transition. If you have weak feet, which I'm going to guessing you do, you if you go if you suddenly that's the only shoe you wear all the time, you'll probably regret it, right? So, so slowly slowly slowly increase the percentage of time that just like anything else, right? If you if you like suddenly decide to lift, you know, huge weights that you can't lift before, you'll hurt yourself, right? The same thing is with your feet. So, so slowly it does it, but you if you do it gradually and slowly and carefully, you can build up strength in your foot and and you'll and you'll be a happier happier person. And this is this goes back to everything else you've said about how choosing comfort, choosing to have a nice supportive shoe has actually just kind of deferred a problem off into the future for me. It's the same with diet. It's the same with avoiding and being sedentary and and all these other things where when you choose the easy road in the short term, which is this wonderful cushioned shoe I've chosen, the muscle hasn't built up in my foot, and I've paid the price. Correct. So, I need to again choose discomfort more in the short term, go up the stairs, run barefoot to avoid the late the consequences later down the line. Yeah, I mean, I don't think you have to run barefoot, but though it can be fun, but um um but yeah, I mean, and I can think of plenty of other examples. Um We love comfort, but comfort's not necessarily good for us. When you um when you look at these tribes, are they Do you know who Liver King is? Huge massive muscles, talks about ancestral living. Um What do our hunter-gatherer ancestors look like in terms of that? Not like him. No? Okay. I mean, look, think about it. Muscle is really expensive, right? It's actually a super expensive tissue. Uh about a third of our body is muscle, and it's using up about about you know, a fifth or more of the calories that we're expending, right? Uh just just sitting there, not even using them, right? They're they're very costly tissues, right? And so, if you have more muscle than you need, you're basically adding to your your cost of of living, right? And if you're if you're a hunter-gatherer or even a subsistence farmer living on the margin of food security, having more muscle than you need is actually deleterious, right? Remember, the only thing that natural selection cares about is how many offspring you have who survive and reproduce. Doesn't care if you're strong or healthy or nice or loved or, you know, fun or whatever. It only cares about whether you have grandchildren. That's it, right? That's the cold calculus of selection. My brain is going if I have big muscles, I'll have more romantic opportunities, and I'll have grandchildren. Well, only up to a certain point, right? And I don't So, if more muscles if if they attract the opposite sex and and make them want to reproduce with you, yes, that could be a benefit. Um I'm not so sure how much women are attracted to the Liver King, but um um and that's not something I even want to know the answer to, but um and certainly shouldn't ask him, but um um um but but there's a reason we have use it or lose it, which you mentioned earlier, right? Because when we need when we increase our demand, we increase our capacity, right? When you go to the gym and you work out, right? You build muscle, but if you stop using those muscles, you lose it. And that's an adaptation, right? Because you don't want to spend extra energy on muscles you're not using, right? So, you want enough but not too much. You want to be economical with muscle mass, right? Um and so, uh if you look at the data um from hunter-gatherers, and people have done that. They've done grip strength tests, etc., and all kinds of other fun things with it. Like mini Olympics. I mean, we've done this, too. Um People are reasonably strong, but they're not super strong. And they're not they're not buff and built and bulked and all that sort of stuff. They've got enough muscle to do what they need to do, but no more. And the reason why people find muscle attractive anyway is because it's a evolutionary signal, isn't it, of uh reproductive value and resources, maybe, and your ability to go out and Do you know what I mean? Why why does why does a woman, for example, find a man with muscles or in good shape attractive in 2023 when we're not hunting for gazelle? Well, I'm not a I'm not a I'm not a psychologist or a or so, I'm not sure if I'm qualified to answer that, but I could I could venture the guess that obviously, if you're trying to if, you know, we pair bond as a species, and we have been for for of years probably. You want to pair bond with somebody who's going to because we also have of cooperation and food sharing, right? You want to prepare bond with somebody who's going to be able to you know bring home the bacon literally and figuratively, right? But but bringing home the bacon does not mean looking like Arnold Schwarzenegger at least back in the day Arnold Schwarzenegger back in the day, right? Being bringing home the bacon back in the day meant being a persistent hunter being able to run long distances and being moderately strong. So they looked more like a marathoner or or a football player than they did a weightlifter, right? So it's conceivable it's conceivable that someone who is really really big is actually um less attractive because they wouldn't have been able to hunt and run and hunt as well as someone who was a little bit Yeah, you also have to you have to feed what they you have to feed them more, too. Yeah. And that's a you know those are precious calories. So I'm going to guess that uh I look if you look in in in non-Western populations you don't see physiques like that. This is a this is a privilege of people who are able to go to gyms and and you know eat you know you know whey powder shakes and all that kind of stuff to kind of build their crazy muscle mass, but it's not something that our ancestors were able to do on a regular basis. That's for sure. A quick word on Huel. As you know they're a sponsor of this podcast and I'm an investor in the company. One of the things I've never really explained is how I came to have a relationship with Huel. One day in the office many years ago a guy walked past called Michael and he was wearing a Huel t-shirt and I was really compelled by the logo. I just thought from a a design aesthetic point of view it was really interesting and I asked him what that word meant and why he was wearing that t-shirt and he said this is brand called Huel and they make food that is nutritionally complete and very very convenient and has the planet in mind and he the next day dropped off a little bottle of Huel on my desk and from that day onwards I completely got it because I'm someone that cares tremendously about having a nutritionally complete diet but sometimes because of the way my life is that falls by the wayside. So if there was a really convenient reliable trustworthy way for me to be nutritionally complete in an affordable way I was all ears especially if it's a way that is conscious of the planet. Give it a chance. Give it a shot. Let me know what you think. There's another myth that I you bust which I thought was really interesting cuz I think I know a lot of people that have used this as a as a reason not to run. They say it's really bad for your knees. Oh man, that gets me so mad, right? I mean I hear this from doctors all the time, right? Oh yeah, running is bad for your knees. Now it is true that knee injuries are the most common running injuries. Um um but arthritis which is really what they're usually talking about um it's absolutely definitively not true that running increases rates of knee cartilage damage and arthritis. So arthritis is caused by cartilage wearing away in a joint, right? And it's it's a it's a myth that that running actually increases cartilage damage. If you have arthritis running is excruciating and problematic, but if you don't have it running actually if anything may be slightly preventive um because cartilage joints like everything else benefits from being used, right? And so physical activity actually helps promote strong and healthy joints. We used to think that it just caused them to wear away, but actually you know like cars you're wearing away at their tires, but now we know that actually physical activity promotes repair mechanisms in cartilage just as it does in other tissues in the body. And um um and of course the other thing about running is that I think a lot of people run incorrectly today. So so that's why we started studying barefoot running millions of you know a long a few a bunch of few decades ago is because if humans have been running for millions of years most of that time we were running barefoot. So I'm kind of curious how did people run before shoes and what we learned was that today shoes have these cushioned heels that enable you to essentially run the way you walk, right? You land on your heel. And everybody who's barefoot sometimes lands on their heel, but people who are barefoot often more often than not land on the ball of their foot and then they'll let their heel down. It's called a forefoot strike or a midfoot strike. And when you do that we worked out the biomechanics of that and published a paper on the cover of nature showing that when you do that you actually prevent your foot from crashing into the ground causing a what's called an impact peak collisional force. You run lightly and gently. So if you were to take your shoes off and run up Lexington Avenue here I guarantee you you would not be landing on your heels within a few steps you'd start landing on the ball of your foot because it hurts less. And so that's how we evolved to run. You we evolved to run in a cushion in a way that that doesn't involve you know slamming into the ground with every step. And the and that that causes less force around your knee. Um the trade-off though cuz nothing comes for free everything has trade-offs is that it's harder on your ankles. Your calf muscles and your Achilles have to do now a lot more work to let your heel down. And so people who switch from heel striking to forefoot striking often have Achilles tendon problems. They get calf muscle problems. If they don't do it properly they'll get if their foot muscles aren't strong enough they'll get all kinds of foot problems, right? So you can't just suddenly become a barefoot runner and start forefoot striking. If you're going to switch you have to switch gradually and slowly and build up strength and learn to do it properly. Another thing people do is they tend to run like a ballerina high up on their toes. That's really hard on your ankles and your calves. So you got to do it properly, but if you but it can have enormous and so and we know again if you run that way this puts much less force on your knees and again knees are where people get injured the most. So I think a lot of knee injuries come from um from the way in which we run. So would you recommend if you can to run more barefoot especially if you have those kind of shoes we just discussed? Well, I think what matters is how you run not what's on your feet, so I would say a barefoot style How do I learn to run in a new way though? Well, I mean there's some tricks. So one of them is first of all I don't know how you run so I so maybe maybe you already run just fine. But a barefoot style tends to be a high stride rate or high stride frequency. So 90 strides per minute or 180 steps per minute roughly. You know um 170 to 180 steps a minute is about right. Um relatively short strides so you're not throwing your leg out. And to me the most important thing is not what we call over striding. You ask any coach on the planet they'll say over striding is bad. Over striding is when you throw your leg out way in front of you when you land and that leg is a stiff leg. So that a stiff leg means more force, right? Um and and and it's harder on your knees. Um and so if you and so a good runner lands uh with their with their shank with their tibia vertical. So their ankle is below their knee. When you do that pretty much everything will work out properly, right? Um it'll mean that you won't land hard on your heel. It'll mean that your your leg will be acting like a excellent spring. You won't be producing a lot of breaking force. Um it's a it's a it's to me I think the most important skill in running is not to over stride. Um and um so I actually tell me so don't worry about how you're going to hit the ground. Just worry about your over stride. If you solve your over stride you're more likely to run well. What do you think some What's the best kind of sort of cardiovascular exercise for the promotion of good health? And cuz I've been doing some CrossFit stuff. I've been doing some hit workouts. I've been trying not to run because I've had a few injuries. I'm trying not to run as much cuz it seems to be a little bit more impact than if I'm bullshitting myself there, but um so I've been doing some like hit workouts every for 30 minutes a day when I leave here. You do hit you hit hit hit works every single day? Pretty much every day at the moment. We track it with a group of friends we have. There's 10 of us in the WhatsApp group. Whoever's last whoever does the least workouts every month is evicted and there's a raffle so there was a raffle yesterday on the 1st. Was it the 1st yesterday? Yeah, for a new member and we do that every month and we've done it for 3 and 1/2 years. That's great. I've been in there I was the first ever member so I've been in there for 3 and 1/2 years. Well, I think you know I mean the most the best exercise the one you like doing. Yeah. But is there one that's like better you know like the You know I think you got to mix it up. There is no one perfect exercise, right? I mean I think what you do it sounds actually pretty good, right? You got a mixture of of of you know low slow intensity some some high intensity. You want to have some strength training. You want to have some cardio. I mean we never evolved to do one thing and our bodies are too complex to benefit from just one thing. Uh mixing it up is is the obvious way to go, right? I think the bedrock for any kind of physical I mean you ask anybody, right? Cardio is the bedrock of of of of of of exercise, right? It it promotes the most health benefits, right? It's good for your good you know you're burning energy. It's good for your cardiovascular system. It's good for controlling inflammation, but but but there are different kinds of cardio in high intensity versus low intensity and there's also strength training, right? Which is also you know important. So you know there's no you know look we tried to medicalize exercise, right? It's like a like there's a proper dose, right? You know take this pill this many milligrams this many times per week, right? Exercise it doesn't work that way. There is no there is no optimal dose. Everybody's different. Depends on are you more worried about heart disease or Alzheimer's or diabetes or depression or you know are you previously injured? Are you fit? Are you unfit? There is it's impossible to prescribe exercise in this kind of medicalized way. It doesn't work. A lot of people exercise because they believe it will help them to lose fat. Uh one of the biggest debates on the planet. It has been a huge debate even on this podcast. I've had multiple people come and say a whole range of things about weight loss and cardio. And I'm kind of I don't know what to believe anymore. Well, anybody who wasn't confused doesn't understand what's going on, right? You know, it's um it's sad that there's such a debate um but um but that's how science works, right? So, um as you know, I wrote about that in in this book um part of the explanation for the debate is that again, what dose are you analyzing and what population in what kind of context, right? So, the pretty much every major health organization in the world recommends that you get 150 minutes per week of physical activity. That's kind of like the benchmark. That's what the you know, the WHA WHO, the World Health Organization considers the the division between being sedentary versus active. So, and and a lot of people are unfit and overweight and struggling to be physically active have struggled to get 150 minutes a week, right? So, a lot of studies prescribe 150 minutes a week of exercise, walking for example, a moderate intensity physical activity. And then look at the effects on weight loss. And guess what? When you when you walk 150 minutes a week, which is what? 20 minutes a day of walking, which is about a mile, a mile a day, you're not going to lose much weight. You're basically burning about 50 calories a day doing that, right? That's a piddling amount of calories compared to drinking a glass of orange juice, right? So, so surprise surprise, those kinds of studies show that those doses of physical activity are not very effective for weight loss. However, plenty of rigorous controlled studies that look at higher doses of physical activity, 300 minutes a week or more, find that they are effective in losing for helping people lose weight, but not fast and not large quantities. So, you're never going to lose a lot of weight really fast by exercising. It's just not going to happen. Because, you know, a cheeseburger has what, you know, 800, 900 calories. You have to run, you know, 15 km to lose that to to burn the same number of calories. You're going to be hungry afterwards, too. So, you're going to make some of that back. You have compensation. So, so physical activity is a is actually there's just no way around it. You have to be a flat-earther not to argue this way. But there you know, there physical activity can help you lose weight, but it's not going to help you lose a lot of weight fast and not at the low doses that often are prescribed. But the one thing that we do agree on, and I think this is would not be controversial, is that physical activity is really important for helping people prevent themselves from gaining weight or after a diet from regaining weight. And there are many, many studies which show this. One of my favorite was a study that was done in in Boston on policemen. You know, policemen are kind of have a reputation for, you know, having too many donuts and being overweight, right? And Boston is no exception. So, they did this great study at at at Boston University, right across the across the river, where they got a bunch of policemen on a diet, a really severe diet. The policemen all lost weight, but some of the policemen were were had to diet and exercise, some just dieted alone. And as you might imagine, the ones who dieted plus exercise lost a little bit more weight, not a lot, just a little. But and then they tracked them for months afterwards because most people after a diet, their weight comes just crashing back, right? The policemen who kept exercising even after the diet was over and they went back to eating whatever the hell they wanted, donuts, whatever, they're the ones who kept the weight off. But the ones who didn't exercise, whoosh, the weight came crashing back. Another good example would be the Have you ever seen the TV show The Biggest Loser? Uh, yes, where they where people go and lose weight. Yeah, so that so this crazy show, right? These people, you know, this is like totally unhealthy. They were confined to a ranch in Malibu and these guy these people lost ridiculous amounts of weight. Guy named um Kevin Hall at the National Institute of Health studied them for for for years afterwards and looked at and most of them regained a lot of the weight that they lost. And there was one person on the show who did not. And that was the person who kept exercising, right? And that's you know, just yet more one one data point, but there's a lots and lots of evidence to show that physical activity, what its other important benefit when it comes to weight is is preventing weight gain or weight regain. When we talk about dieting, we talk about exercise or diet, exercise or diet. Like why is it an or? I mean, why isn't it exercise and diet? Diet is of course the bedrock for weight loss, but exercise also plays an important role and should be part of the mix. On the um police example and the biggest loser example, I can relate in the sense that when I exercise, when I go through the the moments of my life where I'm most committed to exercise, I'm also most committed to my diet. Yeah. Because I if I go to the gym, I will not then leave the gym and have a donut or a pizza. Absolutely not. It seems like wasting the effort. So, if you look at the sort of correlation between the moments in my life where I eat healthiest, they're also the moments in my life where I'm most most focused on the gym. And I noticed there was a couple of months ago, had a bit of a motivation slump. Managed to stay in our little WhatsApp group, but coasted down the bottom of the leaderboard for a bit for a couple of months on end just like surviving every month by one. Um and through those moments, my motivation in the gym had gone down and my diet had gone down. The minute I managed to get in the gym and do a big workout, the same day my diet came back. Yeah, of course, right? And they covary, right? And and that's one of the reasons why when people do big studies of of, you know, what you know, you can look at what what what people die of, right? What's on the death certificate, you know, cancer, heart disease, whatever, heart attack. Um and then you look at what caused the cancer, what caused heart disease. When people try to do that, it's almost impossible to separate diet and exercise because people who tend to eat better also tend to exercise more. They're both in our modern upside-down, topsy-turvy world, they're both markers of privilege. People who have money to go to the gym also have money to buy healthy foods. And um um um you know, about their physical activity also tend to care about their diet. So, so at that level, they're very hard to separate. However, if you're studying a particular component of a system in a randomized controlled trial in a lab, you can separate them out. And so, we know that they have independent and also interactive effects. What is the um the most important thing we haven't talked about, Daniel? I think the most important thing is that we need to be compassionate towards each other. I mean, there's so much shaming and blaming and prescriptions and you know, um um you know, the reason I entitled the book Exercised is that people we make people feel exercised about exercise. We make them feel uncomfortable and un- confident and shamed and and you know, here you and I are having this conversation, but I can tell that you you take you know, you're you're I mean, I know I've listened to enough of your podcast, you care about your your health and you care about diet, you care about exercise. And people may look at you and think, "Gosh, I wish I was like him, but I it's just not me, you know, I can't I'm not I'm not there, right?" And they may feel put off by our conversation. And I think that so often these discussions make people feel feel bad about about what they're doing. And I and I and I and I and I think that what we need to emphasize is that if you put a you know, if you put a chocolate cake and an apple in front of me here, I would want to eat the chocolate cake. And I would I might eat the apple only because you're there. But if you weren't there, I would eat the chocolate cake, right? And and and when I'm in the in the in my building at in at Harvard, my office is on the fifth floor of this old Victorian building. Every single day I want to take the elevator. And the only reason I take the stairs is that if anybody catches me in the elevator, I'll be a hypocrite. It's not that I don't want to take the elevator. I do want to take the elevator, right? I guess you guys say lift, right? Um and and and we make people feel bad for taking the elevator, right? Um they shouldn't feel bad. It's an instinct. And so, I think we have to figure out ways to help people without shaming them and without blaming them and without without bragging and whatever, make you know, you know, talking about, you know, the marathon they ran or this, that, or the other. Make them feel um less uncomfortable about the topic and realize that you don't have to swim the English Channel or run a marathon or, you know, join your WhatsApp group and do crazy hit workouts every day. By the way, you don't need to do hit workouts every day to get the benefit. Um um instead, just, you know, taking the stairs in your building every day. You know, anything is better than nothing. And and you'll get benefits from that. And I hope that that's the message that needs to get out, right? Anything is better than nothing. And if you can get started on that on that on that pathway, then it'll it'll eventually become self-rewarding. And and that and that leads me to the other topic that we didn't talk about, which is that the reward system of physical activity. You know, you and I, if we go for like I'm I'm really looking forward to my run tomorrow morning in the park. I love running Central Park. It's one of the best places in the world to run, right? A fantastic view from the top and it's just gorgeous, right? Um but when I run Central Park tomorrow, I'm going to get a big dopamine hit. I'm going to my body is going to produce all this dopamine, which is the molecule that says, "Do that again," right? It's a reward. Gamblers get dopamine hits, right? Um people eat chocolate cake get a dopamine hit hit, right? But if I were unfit and overweight, I wouldn't get that dopamine hit. And so, when people start exercising, they don't get the reward that people who are fit and and custom to doing it get. And then they're made to feel bad like, "You didn't enjoy your run around Central Park?" Well, it takes months if not years before you actually get that reward. Really? Yeah, because because uh just like being overweight um causes you to become insensitive to insulin, you become insensitive insensitive to all kinds of other hormones and neurotransmitters and dopamine is one of them. So so it it's not an instant like benefit, right? It's hard. And so we need to be compassionate again towards people who are struggling to become fit and struggling to get their reward. And also if you're overweight and you run around Central Park, it's like like if I were carrying weights and running around Central Park, it'd be much harder, right? It's you know it's it's challenging and so we once you get a you know into that state, it's hard to get back to the state of activity. And so we we need as a as a society to to to help those folks rather than judge them. Those folks that are struggling and I was one of those folks that were struggling for many many years. I would say to myself every year um pretty much all of my adult life that this was going to be the year that I'd get fit. I tried all of these various different you know fad exercise things, buy all this stuff. I announced in 2017 that I was going to work out every single day. And that lasted for 6 months and then I yo-yoed back out of that. It never stuck with me until 2020 and that's I've been exercising 6 days a week since 2020, 82% of days. And um I reflect and try and diagnose how I went from someone who what was it that changed? And if I can figure out what it was that changed at the most fundamental level in my mindset or my attitude or my life or whatever it was then I can help other people figure out that too or at least give them more sound advice or at least be more empathetic, whatever's required to help them. You know, and I have a platform here where I speak about exercise a lot in these things. So what's your suspicion? What's your suspicion on what it is that makes people go from being you know maybe having a um a negative opinion towards exercise or their ability to be disciplined with it to becoming an exerciser. Do you know? I have this is a question that obsesses me. In fact, we have a big project right now, a big grant to actually study this right now um because I the more I study it, the more I think it's social. The more I think that um um again, I think people are physically active I in our modern world exercise for two reasons. One, it's necessary or rewarding. And what makes it rewarding for most people is the social aspect. And that social aspect can take many dimensions. It can be running with a group of friends and you know you might want to go on the a mile but your friends convince you to to run another mile, right? And you end up running 2 miles, right? Or you're feeling bad and crappy and you're you know your friends help you do it. Or I'm I'm running buddy, right? And I often you know meet meet friends for early morning runs and I can tell you that the evening before it seems like a great idea to meet Aaron at 6:00 a.m. on the corner of Mass Ave and Linnaean. The next morning at 6:00 a.m. I want to stay in bed with my wife, you know, I don't want to I don't want to meet this nasty smelly guy, you know, at 6:00 a.m. in the cold and dark. But I I agreed to meet him and out I go, right? And I'm usually glad I did it afterwards. Or um you know, we can go on there other social ways in which which but or dancing, right? I mean nobody thinks of dancing as exercise but it's exercise, right? So that's one important social dimension and the other one though is accountability. Um I describe in the book I'm there's a there's a a friend of mine in San Francisco who was struggling to to to exercise. So she signed up for a a program. It's this company called stick.com. I don't know if you've run across it where it's a commitment contract where you send like $1,000 to them and they keep it in a bank account. They probably invest it and make a lot of money on that too. course. But you set up a referee and and you agree that I'm going to not smoke or this or that or the other or in this case exercise and if you don't do it and your referee is you know what you know keeping track of what you do um you get to choose something negative. So in her case, her husband is her referee and if she doesn't walk I can't remember what by the every day she has to walk a certain number of miles, her husband will will tell her and and or tell the website and it'll send $50 to the NRA that week. Oh my god. And she hates the NRA with a burning passion. What is the NRA? I don't know what it Rifle Association. They're the they're the people who are trying to prevent gun control legislation in the United States and they have effectively prevented gun control legislation in the United States which is now kills more children than cars in the United States. So if she doesn't exercise she sorry, she doesn't do it then then then money goes to this organization that she hates. So this is this is a stick if there ever was one as opposed to a carrot. And I don't think she's every time I see her ask her you know have you have you kept up the walking? She says oh no, the NRA isn't getting a penny. Right? So for her it's been very effective. So it's she's made a commitment contract that that stings, right? That really hurts. Now I don't I think that might be a little on the extreme side and I wouldn't actually recommend that to everybody. But but she's accountable, right? She's made herself accountable in some ways and I think um people can find ways to make themselves accountable to a friend a loved one, a parent, you know priest, who knows what, right? Um you might um or or hire trainer. That's I mean that's kind of what a trainer does, makes you accountable, right? And I think so so those are again social ways to help people be more physically active. So I think there are multiple ways of doing that and I suspect that is going to be the most effective sort of set of tools that will help people. One thing I actually do is the on the screen saver of my phone, it has something that really inspires me. So I see it every day and it's that reminder for me which reinforces my my why across my life. It's actually my my home screen on my iPhone is actually a bit of a mood board for me. We have a closing tradition on this podcast where the last guest leaves a question for the next guest not knowing who they're going to leave it for. And I don't get to see it until I open the book. Um the question is what is one aspect or feature of your life that causes you the most friction /discomfort and how can you change or fix it? I would say um it's my tendency to compare myself to others. Um uh I you know you know life is short, life is precious. We're all experiments of one and uh when I think about when I when I when I engage in that oh so-and-so has such and such um that's um that's a really bad habit. That's a really bad trait. It never leads anywhere good. It only leads towards either either I think about how I have more of something than somebody else that leads to um uh I think uh unhealthy um feelings of pride or feelings of jealousy um you know so-and-so has this award or such and such and and uh that's um that's kind of pernicious. So I think that's a bad habit that I uh I work hard to to overcome. Because it changes your expectations of yourself and that change takes steals happiness. It steals happiness, yeah. It steals happiness. Thank you for the work you do, Daniel. Very important, very very important and increasingly important I think um when we look at the the health outcomes especially here in the United States of people. I mean you actually share a number of them in the book which I didn't didn't we didn't really go into but they're just horrifying. Yeah. It's scary out there. Especially as it relates relates to exercise. Um There was one in particular that I wrote down because it horrified me. I can't remember it was just all the stats around the the current health care epidemic. Only 50% of Americans ever exercise, ever. Really? Ever? Ever. And only 20% meet those very minimal World Health Organization standards. We're a we're a we're a we're a nation of couch potatoes. And the rest of the world is headed our way. But not if they get this book. Because it it I think it is a real perspective changer and it's a real eye-opener and it's a necessary one. So thank you so much for writing it. You're fantastic at what you do. And I'm I'm I'm now a huge fan of your work after delving in deeper and deeper and deeper. Um so I can't wait to see what you do next. Well, thank you. And I recommend everyone to go get this book Exercised because um yeah, I thought I knew a lot about exercise but I but from reading that and having that window into hunter-gatherer ancestors and tribes and other cultures, it really that whole idea of a mismatch life, how mismatched my life is in so many fundamental ways from diet to exercise to socializing. Um and these kind of books help to realign. Well, thank you. Although it it seems that you're doing a pretty good job. Trying, you know. I think we're so far from being human though that there's still a long way to go for all of us. So thank you, Daniel. Quick one. As you know, Airbnb are a sponsor of this podcast and I was actually in an Airbnb last weekend when me and my friends had a reunion in New York. And it's from staying in Airbnbs over the years that led me to start hosting my own place. I know friends of mine who actually Airbnb their own place in order to pay for the Airbnb they use when they're away on holiday which is pretty smart. And maybe you stayed in an Airbnb before and thought this is actually pretty doable. Maybe my place could be an Airbnb. It could be as simple as starting with a spare room or your entire place. You could be sitting on an Airbnb and not even know it. Whether you could use some extra money to cover your bills or something a little bit more fun, your home might be worth more than you think and you can find out how much it's worth at airbnb.co.uk/host. Check it out. Find out how much your home is worth and let me know what Find out how much your home is worth and let me know what you think. Oh.