in: Fitness, Health & Fitness

• Last updated: September 27, 2023

Podcast #691: What You Can (Really) Learn About Exercise from Your Human Ancestors

We all know how indisputably good exercise is for you. Yet a lot of folks still find it a struggle to engage in much physical activity. To understand the reason that this conflict and tension exists and how to overcome it, it helps to understand the lives of our human ancestors. Though, not the way the popular culture understands them, but the way someone who’s actually studied them understands them.

My guest is such an expert guide. His name is Daniel Lieberman, and he’s a Harvard professor of human evolutionary biology and the author of Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding. Today on the show, Daniel shares what we can really learn from our ancestors as to our modern relationship with exercise, while debunking some of the popular myths about our hunter-gatherer history. We begin by talking about how very recent, and actually quite weird, the whole concept of exercise is. We then discuss the fact that our ancestors were not the natural super athletes we typically imagine, what their state of physicality was really like, and how understanding their lifestyle can help us understand the competing interests going on in our own minds and bodies that can leave us feeling ambivalent about getting up and moving around. We then discuss if, as it’s been said, “sitting is the new smoking,” and the less and more healthy ways to sit. Daniel unpacks whether we’re evolved for running, how our ancestors’ strength compares to our own, and whether or not exercise helps us lose weight. We end our conversation with how this background on the past can help us in the present, by showing us the two factors that are critical in helping us moderns make exercise a habit.

If reading this in an email, click the title of the post to listen to the show.

Show Highlights

  • Why the human mind isn’t built for exercise 
  • The myth of the athletic savage
  • How do people in hunter/gatherer societies move their bodies?
  • What’s going on in our bodies when we’re inactive?
  • Is sitting really the new smoking?
  • Are humans built for endurance activities?
  • Were our ancient ancestors jacked?
  • Diet vs. exercise in the battle to lose weight 
  • How to make something unnecessary, necessary 

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Read the Transcript

Brett McKay: Brett McKay here, and welcome to another edition of The Art of Manliness Podcast. We all know how indisputably good exercise is for you. Yet a lot of folks still find it a struggle to engage in much physical activity. To understand the reason that this conflict and tension exist and how to overcome it, it helps to understand the lives of our human ancestors. Though, not the way the popular culture understands them, but the way someone who’s actually studied them understands them.

My guest is such an expert guide. His name is Daniel Lieberman, and he’s a Harvard professor of human evolutionary biology and the author of the book Exercised: Why Something We Never Evolved to Do Is Healthy and Rewarding. Today on the show, Daniel shares what we can really learn from our ancestors as to our modern relationship with exercise, while debunking some of the popular myths about our hunter-gatherer history. We begin by talking about how very recent, and actually quite weird, the whole concept of exercise is. We then discuss the fact that our ancestors were not the natural super athletes we typically imagine, what their state of physicality was really like, and how understanding their lifestyle can help us understand the competing interests going on in our own minds and bodies that can leave us feeling ambivalent about getting up and moving around. We then discuss if, as it’s been said, “Sitting is the new smoking,” and the less and more healthy ways to sit. Daniel unpacks whether we’re evolved for running, how our ancestors’ strength compares to our own, and whether or not exercise helps us lose weight. And we end our conversation with how this background on the past can help us in the present, by showing us the two factors that are critical in helping us moderns make exercise a regular habit. After the show’s over, check out our show notes at

Alright, Daniel Lieberman, welcome to the show.

Daniel Lieberman: Thank you so much.

Brett McKay: So you are a Harvard professor, Professor of Biological Anthropology, you study the evolution of physical activity in humans all your career, and you yourself are someone who’s a marathoner, you’re into fitness, but as you observed in your book, Exercised, a lot of people struggle to exercise, even though they know it’s good for them, they should be doing it, the doctor probably might have said the use for exercising more, and one reason you make this case in your book, our bodies really aren’t evolved for exercise.

Daniel Lieberman: Well, it’s not really so much that the human body didn’t evolve to exercise, it’s really the human mind that didn’t evolve to exercise. So exercise is a kind of physical activity, so physical activity is just moving, right? When you go downstairs to make yourself a cup of tea, or walk the dog, or carry groceries across the supermarket or go hunting or whatever, that’s all physical activity and exercise is discretionary and voluntary physical activity that we undertake for the sake of health and fitness, so we did evolve to be active, it’s just that nobody ever evolved to go for a five-mile jog in the morning or nobody evolved to go to the gym and lift weight whose sole purpose was to be lifted, that’s a really very modern, strange behavior that essentially we created after the industrial revolution, when we created… When we have all these machines that do our work for us, and so people don’t have to do labor anymore in certain parts of the world, and we’ve had to substitute exercise for the physical activity that we used to have to do.

Brett McKay: I feel like your book argues that studying our ancestors can help us wrap our minds around this very modern thing of exercise, but not in the way the popular culture thinks, like part of your book is about what the positive things are, what we can actually learn from our ancestors, and we’re gonna talk about that here in a bit, but part of it’s also about debunking the myths around what we can learn from our ancestors about exercise, and one myth that seems to kind of underlie all the other myths is what you call the myth of the athletic savage, I’m guessing you’re playing off the idea of the noble savage here, what do you mean by the myth of the athletic savage?

Daniel Lieberman: Well, we have this sort of idea, it’s a very popular idea out there that modern human beings, people like you and me, and people listening to this have been contaminated by civilization because we have shoes and Gatorade and fancy watches and all that sort of stuff that we’re sort of no longer kind of great athletes that we were… That humans are normally meant to be, and so you get this idea that if people in… Just like the myth of the noble savage, that people who are uncontaminated by civilization are naturally good and perfect and their children don’t go through adolescence and all that sort of stuff. We have this idea that people who aren’t contaminated by civilization can get up in the morning and just run ultra marathons, and then they’re incredibly strong, and that they don’t get injured and that they’re flexible and… The list goes on, right? And I find that really troubling and disturbing because it’s actually kind of not only is it not true, but it’s also very dehumanizing the people in other parts of the world when they participate in an impressive physical activity and long races or whatever, it’s not easy for them either and they’re working hard, they’re trying it, and they do it because they care, because it’s worth it to them, and I think we need to get rid of this myth.

Brett McKay: Well, so yeah, I think a lot of times when we think about, well, we should exercise ’cause our hunter-gatherer ancestors moved all the time and were strenuous all the time, but part of your work is you go to… We can’t go back in time and see how people tens of thousands of years ago actually lived, but you can look at hunter-gatherer societies that exist today and get an idea of what it was like, so when you actually go visit and you do… And you study like an anthropologist like do the field work, how do hunter-gatherer people actually move their bodies and their level of physical activity?

Daniel Lieberman: Well, so most of my research is not actually on hunter gatherers, I study subsistence farmers, we’ve been looking at the transition from farming to urban lifestyle in Kenya and in Mexico, but I have had the good fortune to go spend some time with hunter gatherers and read the literature, so the data I’ve collected hasn’t really been on hunter-gatherers, I’ve certainly reported a lot of those data in my book, but when you spend time with hunter-gatherers or for that matter, people who don’t have machines and cars and roads and shoes and all that sort of stuff, they’re not actually all that different from us, they’re physically active in the sense that they do have to work, but they don’t work a huge amount every day. A typical hunter-gatherer works about two, two and a quarter hours a day, and if you hang out in camp, which I’ve had the good fortune to do, most of the time people are just doing what we’re doing, which is kind of hanging out, they sit about 10 hours a day, they’re doing chores, they’re taking care of their kids, they’re gossiping, and they’re really out only about half the day doing work, and it’s mostly not that strenuous, and they’re not super strong, they’re just kinda average ordinary people, but they’re struggling to get food, it’s not easy for them to get food.

And so when food is limited, when energy is limited, then you have to engage in trade-offs, just like time, time is a clearly limited resource, so the time that you’re spending listening to me now is time that you’re not spending doing something else that’s probably more useful, and the same is true of energy, right? I went for a five-mile run this morning, just for the sake of going for a five-mile run. But if I were energy-limited and already had to be physically active to actually survive, those 500 calories that I spent, I could have much better used for reproduction, for taking care of my body, for all kinds of good things.

Brett McKay: Well, speaking of running, you begin the book kind of showing the dichotomy of how people think about exercise. So, you talk about us in the West, you go for a five-mile run, just because there’s people who dedicate their lives to training for ultra marathons, and every day they’re running. But then you also talk about, I think it’s the Tarahumara in Mexico. These are the folks, they do, they have a ritual basically where they run a race, a really long race barefoot, oftentimes they’re just wearing sandals, I think Born to Run really popularized that.

Daniel Lieberman: They do not run barefoot, by the way, that’s one of the myths about it.

Brett McKay: Okay, so another myth. But they wear kinda like sandals, right? I think like a very minimal shoe oftentimes.

Daniel Lieberman: Yeah.

Brett McKay: But I think you talk to them and you try to… I think you talked about how you explained them, “Yeah, what do you think about Americans? They run every day, like 10 miles a day, why don’t you guys do that, to get ready for this long race?” And they kind of looked at you like, “That’s weird, why would you run 10 miles every day if you didn’t have to?” I just do this race, ’cause it means something to us, and that’s it.

Daniel Lieberman: Yeah, well, that was really the origin of the book. Look, the reason the book is titled exercised is because people today are exercised about exercise, they’re nervous, they’re anxious, and they’re confused, and they’re fed all kinds of myths, and they don’t know what to think. And I think the biggest myth about exercise is that it’s normal and natural to do, and that if you don’t do it, there’s something wrong with you and you’re lazy. And yes, it is good for you. I’m not arguing that excise is bad for you, but it’s important to realize that just going for a five-mile run for the sake of going for a five-mile run is a very strange and modern behavior. And so that to me was made crystal clear when I was doing… The first time, I went to do research with the Tarahumara and I was talking to some runners and interviewing them about how they get ready to run.

And this was my first time down there, and I was trying to ask them about how they trained. I had my list of… I was being a good anthropologist, I had my list of questions. And everybody was really confused about this question because there’s no… Apparently there’s no word for training in Rarámuri, the language that they speak. And so the translator I was working with was working really hard to try to explain this, and there was this one guy, she was basically saying like, “This gringo, he runs five miles every morning to get ready to run races.” And he looked at me with astonishment, he said, “Why would anybody run if they didn’t have to?” And I remember laughing a little bit out of embarrassment, but that was that moment I suddenly realized, “You know, exercise is yet another one of these very modern things that we have a very sort of strange attitudes towards it.” Yes, it’s good for us, but let’s not pretend that it’s abnormal to dislike exercise. Remember, 80% of Americans don’t get the minimum levels of physical activity that are recommended by every health organization on the planet. And it’s not that there’s something wrong with those folks, they’re actually kind of normal. And we need to understand that in order to help them do better.

Brett McKay: So yeah, running is… Or exercise is weird.

Daniel Lieberman: Exercise is weird. Absolutely. There’s lots of other weird things that we do, think about… Obviously, right now we’re talking over a computer, and reading is weird. Until recently, nobody read. Reading is a completely modern behavior, a few thousand years ago, not a human being on the planet read. Now, our lives are filled with weird things and they’re not necessarily bad, but we have to… It’s useful to step out of our normal life and think about how our world has changed and understand how that affects the way we can do better.

Brett McKay: So, one thing you do in one chapter, you explore how we think about exercise today to figure that out, you explore what happens when our bodies do nothing, when they’re inactive. So, first off, what happens… What’s going on in our bodies when we just kind of not do anything? And then what insights can we get about exercise by understanding what’s going on in our bodies when we’re inactive?

Daniel Lieberman: Well, that’s a huge question, but I’ll try to nail it… Focus on the key issues. The first is when we’re doing nothing, we’re just sitting around on a couch or just hanging out, our bodies are actually doing a lot, two-thirds of the metabolic energy, the energy that you spend every day are just taking care of the basic functions of your body. So, during rest, your body is actually spending a lot of calories, taking care of your brain and regenerating all the cells throughout your body and keeping you healthy and fighting disease and the list is very, very long and you spend about… A typical human male spends probably about 1600-1700 calories a day, just existing. And when we exercise, we do two things, first of all, we spend energy just moving, so muscles, muscles consume a lot of energy, as we all know. So, when we lift heavy weights or go for a run or whatever it is you like to do, you’re spending energy to do that movement, to pay for the cost of the muscle, but you’re also stressing your body.

You’re generating all kinds of little bits of damage, you’re creating little micro-cracks in your bone and your muscle, your mitochondria are producing what are called reactive oxygen species. These are highly reactive molecules that more or less rust your body like an apple when it turns brown, your DNA is mutating, you’re producing waste products like lactic. And one of the things that exercise does is it also turns on all kinds of repair and maintenance mechanisms, that keep our bodies functioning really well. And here’s the key, because we never evolved not to be physically active, nobody ever could be a couch potato 24/7 back in the old days. We never evolved to turn on these repairing maintenance mechanisms as effectively as just sitting around, and so that’s really the key is to why exercise. Physical activity in general, but exercise in particular, is so healthy because without it, our bodies basically break down and physical activity keeps our bodies young and healthy.

Brett McKay: But there’s also a point that there’s… There’s two things going on there. On the other side, there’s like your body, from an evolutionary standpoint, they don’t wanna expend calories or energy that it doesn’t have to expend for survival or reproduction. So, there’s sort of a bulk, you need to move to repair your body and keep yourself physically healthy but it’s like if you go too much. It’s like, “Wow, man, that’s calories I could have stayed… I could have kept on for that famine that’s gonna come in a couple of months.”

Daniel Lieberman: Right, yeah. So, back until recently, people were calorie limited and they struggled to get enough calories, but they were also very physically active because every calorie they got in their body was the result of work that they had to do, you had to go out and forage for plants. You had to go out and get honey, you had to go out and hunt animals, you had to go out and do everything. There was no machines to do anything for you whatsoever. And so there was no way not to be physically active. As I said before, the average hunter-gatherers spends about two-and-a-quarter hours a day in moderate to vigorous physical activity. And so in conditions like that, if you spend any extra energy on physical activity that doesn’t benefit you in some way, that’s not a good idea. So we evolved to be physically active for two reasons and two reasons only, when it was necessary, and when it was rewarding. So our ancestors also played. They danced. They did fun things. But that also has benefits. It has social benefits, it has… Playing is important for developing capacities, play is important for developing social skills, play is important for learning not to be reactively aggressive and learn good sportsmanship. Dancing is, of course… Every culture on the planet also has dancing, and dancing is great for finding mates and enjoying yourself and telling stories and healing, who knows what but…

So those are the reasons we were physically active. But going to the gym… And for me, the obviously sort of apotheosis of sort of how absurd exercise is is a treadmill, that’s why it’s on the cover of the book. Because a treadmill, think about it, you pay a lot of money either to go to a gym or buy one yourself to work on a machine that gets you absolutely nowhere, gets… It’s good for you, but it’s a very, very strange thing. Imagine trying to explain that to your great-great-great-great-great-great-grandparents

Brett McKay: So that’s part of the reason why what makes being motivated to exercise so hard, at least the way we think of exercise today. It’s like there’s not really any immediate reward. Doesn’t get you food, doesn’t allow you to survive, and if you’re on a treadmill, it’s like, well, that’s not really motivating, so you’re just like, Well… Your body’s like, Well, you know what? Not really worth it. I think I’ll just sit on… I’ll just stay home and take it easy.

Daniel Lieberman: Yeah, absolutely. [chuckle] I hate treadmills. I put people on treadmills for a living, and I can’t stand using a treadmill. I always… I have to coerce myself in various ways. I have to watch something on TV or listen to a podcast or something. It’s the only way I can ever tolerate a treadmill.

Brett McKay: Alright. So we need to move for health, for survival, but again, there’s this sort of battle. We don’t wanna move too much ’cause there’s no immediate reward for that, and we need to save calories. So we’re battling against that a little bit. Going further in this idea of inactivity, one thing you’ve seen people or health websites, magazines, books hit really hard is this idea of that sitting, sitting is the new smoking. And we’ve had… I think we’ve had someone… We’ve had a podcast about this. I’ve talked about the benefits of standing desks on the website. And so when I read this, like, Well, is sitting really the new smoking? What does the research say about that?

Daniel Lieberman: Yeah. So I think sitting is a… It’s like a perfect example how we make people exercised about exercise and health and bodies, etc. Look, everybody knows, you don’t need to be a scientist or a doctor or whatever to realize that too much sitting is bad for you. That’s kinda obvious, right? But what we’ve done is to exercise people about it. We’ve now claimed that sitting is the new smoking, and that your chair is out to kill you. And you don’t… If I were just an average, ordinary person hearing somebody tell me that sitting is like a cigarette, I would get suspicious ’cause it’s obviously… A cigarette is a form of toxin. It’s poison that you’re ingesting into your body. And how can something as normal and basic as sitting be that bad for you?

And I think if you look more carefully at the data, it turns out that, yes, if you sit too much, that’s a problem, but it’s actually mostly leisure time sitting which is associated with negative health outcomes. So people who work at a job, and then… Are sitting at their desk much of the day, they’re doing fine if they’re still exercising and walking to work and doing all those other sorts of things. The folks who are really in trouble are the ones who sit at their desk all day, and then when they… And then also they’re sitting in their car to get to work, and then they’re sitting in their car to get home, and then they’re sitting all evening long, and basically, they’re never doing any physical activity. So that’s one issue. We shouldn’t demonize sitting.

Secondly, it turns out that sitting is completely normal. My dog spends the day sitting all over the house. Hunter-gatherers sit 10 hours a day. So let’s not pretend sitting is something abnormal and modern. And then third, it turns out that there are healthier and less healthy ways to sit. So many studies show that what really matters is how long you sit for, what’s called active sitting. So you and I might both sit 10 hours a day, but if I get up every 10 minutes and you get up only every 40 minutes, my health outcome is gonna be much, much better than yours. And that’s because you’re turning on… When you turn on muscles, even just a little bit, it’s like turning on your car, you’re turning on all kinds of… And you’re turning on the engine, you’re using up some fats and sugars in your blood stream, you’re turning on all kinds of genes. It’s really healthy. Or if you’re sitting in a chair that requires you to use some muscles. Right now, I’m sitting at the edge of my chair, I have a standing desk, and I often stand up, but I’m not using a back rest. And so I’m having to use back muscles to kind of stabilize my upper body. And again, that’s using a little bit of energy. It’s not a lot of energy, but it’s still kinda healthier than the kinda more passive sitting that people do. So let’s not tell people that sitting is the new smoking. Let’s help people get the correct information about how to sit a little bit more healthily and stop scaring them.

Brett McKay: Well, and you… What I love about this chapter too is you explore, okay, if you’re inactive or you sit for a long period of time, that leisure sitting, you get into the research, what’s going on, why is it bad for your body, and it basically… It’s your body, there’s just a low-grade inflammation going on when you’re inactive for long periods of time, that can cause all sorts of problems.

Daniel Lieberman: Correct, exactly. So sitting can be pro-inflammatory for two reasons. The first is that you can add fat. So if you’re sitting all day long and you’re not getting any exercise, any excess energy you’re taking in, well, your body will store as fat, and that fat can cause this kinda low-grade inflammation. Basically, your body is starting to attack yourself. And then the other reason is that if you’re not being physically active and you’re not using your muscles, turns out your muscles are the major tissues, the major tissues that actually produce molecules that turn down inflammation, they’re called myokines. You have a lot more muscle than white blood cells, which are also regulating inflammation, so when you’re active, you’re not only preventing yourself from storing up excess fat, which promotes inflammation, you’re also turning on your muscles, which then turn down inflammation. So, sitting a lot and being physically inactive is kind of a double whammy in that regard. But here’s the good news, you don’t need a huge amount of physical activity to get those benefits, it’s not like you have to run a marathon or go to the gym and lift ridiculous amounts of weight, do CrossFit workouts, and there’s nothing wrong with any of that sort of stuff, but you don’t need that to get the benefits.

Brett McKay: So, don’t beat yourself about sitting down. Most of humans around the world, even hunter gatherers, they spend a lot of time sitting, they just are a little bit more active when they sit.

Daniel Lieberman: Yeah, yeah, it’s not really very complicated.

Brett McKay: Well, here’s a question, so I’ve got that feature on my iWatch where it reminds me to stand. Am I exercising myself? It might be an exercise by sitting by having that feature, is that… Do you think that… Is that helpful?

Daniel Lieberman: No, it’s cool. It’s fine, I mean look… Whatever makes you happy, right? There’s lots of ways to use technology, and I’m not opposed to technology, and just because it’s new doesn’t mean it’s bad. Yeah, I try to find ways to force myself to get up every once in a while too, and I don’t have an iWatch, but I intentionally have a coffee mug that gets cold, so I go and warm it up again and things like that, or my dog comes and bothers me on a regular basis, and I have to scratch her, I’m constantly trying to get up, I’m a fidgeter too so that helps me. But whatever works for you is fine. There’s no… We shouldn’t be… Let a thousand different ways of interrupting your sitting bloom, whatever works for you.

Brett McKay: Well, the other idea you explore in the book is how there’s this idea that humans were evolved for endurance activities, and they’ll point to persistent hunters. I think people have seen that YouTube video, I think it’s in Africa, these guys who just chase this gazelle or this antelope for miles until it just passes out and dies, and then they do it like, “Well, yeah, if humans evolved to do that, well, then maybe we should run ultra marathons.” The conclusion. Can you talk about what we know about humans and endurance activities and is it… Should we make that… I imagine the answer is no. Should we make that jump from, “Well, we did really good at persistent hunting, so maybe we should also run ultra marathons?

Daniel Lieberman: Well, I’m partly to blame for this idea ’cause the research that I’ve done for many years, it’s been on the evolution of hunting and we were the… My colleague, Dennis Bramble, and I published that paper in Nature in 2004, which was entitled Born to Run. That kind of got a lot of this started. And I do believe there’s no question that humans evolved to run long distances, and we evolved that around two million years ago in order to become scavengers and hunters. It’s really important for us, and we have all kinds of adaptations in our bodies, literally from our heads to our toes that make us exceptional at long distance running, but they didn’t do that on a regular basis, they didn’t do it really fast, and you don’t necessarily need to do that in order to get the health benefits of physical activity. So, if you like to run marathons, which I do, that’s great. If you like to run ultra marathon, that’s also great. But we have this idea that just because our ancestors did those kinds of runs, that that’s something that we necessarily have to do, and that’s certainly not the case.

It’s something that’s built into us and endurance is definitely important for human health, if you look at every study of the effects of physical activity on health, there’s no question that cardio, that endurance physical activity is sort of the bedrock of every major program, and it’s really good for you in a thousand ways, it’s good for your brain, it’s good for your metabolism, it’s good for your cardiovascular system, on and on and on. And in fact, we’ve published studies which show that even if you do a lot of weight training, it’s the absence of cardio that can result in some degree of health risk. So, everybody should do some cardio, but you don’t need to do an enormous amount of cardio to get the benefits.

But on the other hand, if you like doing ultra marathons or marathons, that’s also fine too, and people are always worrying about if you can exercise too much, really, there’s very little evidence that you can exercise too much. Of course, there are very few people who actually get out there in terms of those distances, and so there’s not a lot of information really.

Brett McKay: Well, can we backtrack a little bit? Like talk about the adaptations that make us great endurance athletes.

Daniel Lieberman: Oh gosh, we could talk for hours about…

Brett McKay: Like sweating is one. So, humans can sweat, most animals can’t sweat. What else has made us good?

Daniel Lieberman: So, we have thermo regulatory adaptations, we have metabolic adaptations. We have genes that help us have higher aerobic capacity, in terms of musculoskeletal adaptations, we have springs in our feet, we have long Achilles tendons, we have short toes, the gluteus maximus, which most of us are sitting on it, that’s a muscle that’s enlarged in order to make us really good at running. We have specialized stabilizers in our head, our arms, when we pump our arms, we have abilities to actually use our arms to balance our head, to keep our heads from bouncing so much. We have a ton of features in our bodies that make us really, really good at long distance running, and that we can see many of these evolved around two million years ago and have been important parts of our evolutionary history until recently, pretty much running was something that everybody had to do, you couldn’t be a hunter back in the old days unless you could run and hunting was a very important part of our evolutionary history.

But we live in a world today where we don’t have to do that anymore, and a lot of people have lost the skill of running very well, which is too bad, ’cause I think it’s the most fundamental basic kind of vigorous physical activity. But yeah, so it’s certainly part of who we are.

Brett McKay: And part of your research, you raised a horse in a long distance… Or a bunch of horses in a long distance race.

Daniel Lieberman: Yeah, that wasn’t so much for research, that was kind of put my money where my mouth was, ’cause I’ve been writing about persistence hunting, and I’m not gonna try to run a kudu down in the Kalahari, that’s actually illegal. So, I thought what I would do is try to join one of these men against horse races, so I ran one in Prescott, Arizona a few years ago, and I had a blast, it was a lot of fun.

Brett McKay: And you beat some horses.

Daniel Lieberman: Yeah, it was actually not too bad. Look, I’m a middle-aged professor, I’m not a super fast runner by any stretch of the imagination. And there were, I think, 41 runners and 53 horses, I think that year, I can’t remember the exact numbers, and I beat all but 13 of the horses, so I beat like 40 horses and the horses by the way get a veterinary check-up, which is subtracted from their time, which the runners don’t get. So, we had kinda… Horses had like a handicap.

Brett McKay: So, another idea that is out there because of this athletic savage myth is that hunter gatherer ancestors or cave men ancestors, whatever you wanna say, they were a lot stronger than we are today. What has your research found about that?

Daniel Lieberman: Well, they’re not. And it’s actually kind of easy to explain why. Look if you spend time with foragers, they’re certainly strong, they’re not weaklings by any stretch of the imagination, and they’re also kind of thin too, so their muscles really pop out too, but they’re not jacked up. They’re not like weight lifters, and in fact, it would be problematic for them to do that, because muscle is really expensive, if you… Anybody who’s gone on a serious weightlifting regime and really trying to bulk up, you know you have to eat a lot more because muscles are very expensive, they’re costly tissues. And so extra muscle… The reason we have this kind of use it, lose it kind of biology is that you wanna put on muscle and you need it, but you don’t want any extra muscle for when… Because otherwise you have… You need hundreds of extra calories every day to pay for that… All that muscle mass, right? And if you’re struggling to get enough calories, too much muscle is just not a good thing. And the kinds of tasks that our ancestors did required some degree of strength, but not a huge amount of strength.

So, hunter gatherers are… They’re moderately strong, they’re like grip strength tests suggest they’re about 70-50th percentile for standard Americans or reds or something like that, but the key thing is that as they age, they remain relatively strong because they’re still using their bodies as they get older. Whereas a lot of Americans, for example, as we get older, we end up getting a disease called sarcopenia where we get wasting of our muscles, and that is a really serious thing because that kind of frailty leads to a vicious circle. We’ve all seen elderly people who have trouble getting out of chairs and they end up walking really slowly and tasks become more difficult, they become compromised in their ability to function. And when that happens, then you become less physically active, which keeps driving that cycle forward. And so as we get older, it’s… Exercise is not less important. Exercise becomes more important, and that’s one of the reasons why it’s so critical as we get older, in this modern world where we’ve got machines to do everything for us, that we do weights, right? It’s good to do at least two bouts of resistance training a week as you get older in Western environments like ours, because it prevents that kind of muscle wasting, it’s really critical.

Brett McKay: Now, this chapter resonated with me because I lift weights, that’s my chosen modality of physical fitness. And yeah, muscle is… The worst part of… I do power lifting. The worst part is often the eating part, ’cause you’re still like eat all… And you’re like, “I don’t wanna eat this, I don’t wanna eat this,” but if you want to… And then also, my coach, my barbell coach makes this point about when it comes to strength training, he says, “With strength training, there’s like a meter,” like you’ll reach a point where, okay, you need to do strength trainings for general health if you’re older person, so you can get up off the floor, get up off the toilet, avoid that, what you talked about the degradation of muscle. But then he says, “There’s a point where strength training becomes unhealthy and you’re basically training for competition.” He says, “You don’t need to deadlift 600 pounds, but if you want to, you have to understand there are a risk of going after that goal.”

And of course, I went after the goal and I did it, I look at what I’m doing, I’m like, I could not do this if I lived in 1700s, this would not be possible, ’cause I wouldn’t have won the food to be able to do it, I just wouldn’t have the time. It’s a luxury when you step back and think about it.

Daniel Lieberman: Yeah, absolutely, yeah. And it’s as strange as you know, my running five miles this morning for no reason at all. So my running five miles this morning was probably a little bit on the healthier side than your trying to deadlift, I don’t know, how many hundred pounds?

Brett McKay: 600 pounds.

Daniel Lieberman: That’s impressive.

Brett McKay: Yeah.

Daniel Lieberman: Not something I ever wanna do. I have to say I struggle to do weights.

Brett McKay: But okay, but the idea though, we do need strength training, ’cause especially as you get older, ’cause you wanna avoid that muscle degradation.

Daniel Lieberman: It’s critical. Yeah, we all need to be like Ruth Bader Ginsburg. And the good news is really cool evidence is that as you get older, it’s inevitable that you won’t stay as strong, but there are studies showing like an 80-year-old people, 90-year-old people when they do strength training, they still get the benefits, they can still put on muscle. Now, you can’t put on as much muscle in your 80s as you can in your 20s, but you can still recruit the stem cells to add muscle mass. So, it’s never too late to try to do this.

Brett McKay: Let’s talk about this other idea that you explore in the book that was interesting. So we got two… I think people have heard two conflicting messages about exercising from the popular health press. One is you need exercise to lose weight, ’cause it burns calories. But then they also see research saying, “Well, actually no, exercise doesn’t do much for weight loss, it’s all diet.” And so they’re like, “What do I… What do I do? Should I exercise?” So, which one is it?

Daniel Lieberman: Yeah, that’s a perfect example of how exercised we are about exercise and how we get fed these little kind of sound bites, this one study comes out, this other study comes out, people just get whiplashed and they get confused and they have no idea how to interpret what’s going on. And weight loss is… Nothing seems to top weight loss in terms of this regard.

So, it is true, if you’re trying to lose weight, you are way better off dieting than exercising because like for example, I went for a five mile run this morning, I burned 500 calories. But if I had just basically not eaten a few slices of bacon, I could have easily have not had those 500 calories. So, it’s just way easier to go into what we call negative energy balance through dieting than exercise. So, that’s kind of where a lot of the, “Don’t bother exercising to lose weight,” idea comes. The other, of course, is true is that when you exercise, you get hungry and so you make up some of those calories that you otherwise spend, which is also true. But it turns out that a lot of the experiments that have been done, have been done on really modest levels of exercise, remember the kind of minimum that everybody recommends is 150 minutes a week, that’s what the World Health Organization says Every human being should do. So, a lot of the studies look at just 150 minutes a week of moderate physical activity, that’s like 21 minutes a day, of going for a brisk walk, which burns like, it burns like 50 calories, it’s not a lot of energy.

And so, surprise surprise people who do that kind of very short, those modest levels of physical activity, which is good for them, they’re not losing weight or they’re not losing very much weight. But studies that look at more exercise do find that it actually is effective for losing weight. And even more importantly… But you’re not gonna lose a lot of it or really rapidly, so if you’re really trying to lose a lot of pounds, exercise is just not gonna do it for you. But you can lose weight slowly and gradually by exercising. But more importantly, exercise has been shown, physical activity has been shown to help us prevent weight gain or weight regain. So a lot of people on diets they lose the weight and then it comes crashing back again after the diet is over, right. But physical activity has been shown to help us not gain weight in the first place, but also to help not regain weight once you’ve lost it. And there are lots of studies, a good one… One I site in the book, for example, is one that was done here in Boston on policeman.

So they had a bunch of policemen who were overweight and they had them go on a serious diet and some went on a diet and exercise, and some just diet alone, and then after that they all lost tons of weight, they all lost a lot of pounds. I can’t remember exactly. And then after the diet was over, the ones who continued to exercise kept the weight off and the ones who didn’t continue to exercise just went right back up to their original weight. And that’s one of just many, many, many studies. So let’s not exaggerate the benefits of exercise for weight loss, but let’s also not completely discount them. And I think that pretty much everybody kinda knows that intuitively too.

Brett McKay: Right. I think so too. So I think what you’re trying to do in this book, and you in your book talking about this, is that you get it going, you don’t want people to be exercised or frustrated or whatever about exercise. And we saw a lot of these myths that we have about exercise in the popular culture, our hunter-gatherer ancestors they ran all the time, and sometimes they ran long distance but most time they sat around just like us. Sitting isn’t bad for you, don’t feel bad about that. Endurance, yes we’re evolved to run long distances but it doesn’t necessarily mean you have to do that, but I think your goal here is you want people to not feel frustrated or flushed about exercise, and you know that exercise is good for them, you want people to exercise, but just don’t beat yourself up about what type of exercise or how much you do.

Daniel Lieberman: Yeah. I mean, look, the way in the modern world what we’ve done with exercise, we’ve done with exercise what we’ve done with so many other things, we’ve commodified it, we’ve industrialized it, we’ve commercialized it, we’ve medicalized it, we prescribe it, and there’s nothing wrong with any of those things. I like to buy fancy schmancy things, and I talked to… Medical… Exercise is healthy, so it’s… Doctors should tell their patients to be physically active. But it doesn’t work for everybody, and medicalizing and prescribing things is just clearly not enough, and it confuses people and makes people irritated and pissed off, sometimes. People nag and brag about exercising, and I call those folks, exorcists.

So really, the argument of the book is to let’s step away from this industrialized, commercialized, commodified medicalized view of exercise and let’s use the lenses of anthropology and evolution to think about it, and when you do that a lot of these myths just disappear, and a lot of these things that are so confusing and complicated just disappear because it’s… We evolved to be physically active, but we also didn’t evolve to run marathons and to do crazy stuff, and we never evolved to sit around all day long, and we’ve often basically moved when it was necessary and fun. So the simple solution is to make moving necessary and fun in this strange world we live in, where now we have to choose to be physically active instead of have to be physically active. And we just made it needlessly. Confusing and complicated.

Brett McKay: Yeah, I think that’s the biggest take away that we can learn from our ancestors, if we wanna start exercising regularly we just gotta figure out how to make exercise necessary and fun. And with the fun part, we’ve had a psychologist on the podcast talking about that, and she just says, “Yeah, do something that you enjoy, but the way you figure out what you enjoy is you have to try a bunch of different stuff and maybe you figure out that you like running, maybe you like weight lifting and maybe it’s yoga, tennis, whatever.” But with the necessary part of the equation, how do you make something that’s unnecessary necessary without infringing on somebody’s autonomy?

Daniel Lieberman: Yeah, well, I had fun going to the Beyond Board Company, which actually requires all its workers to exercise. But I think the way to tell people do that is to make it social. For most people, the things that are most fun are… That’s one of the things that’s been problematic with this pandemic is we don’t see each other anymore, right, but being social is a fantastic way to be physically active. So this morning was a perfect example for me. Every Thursday morning I go running with some friends, we do track workouts, and I didn’t wanna go this morning, it’s kind of cold here and it’s kind of gray, and you know it’s like, “But I have to be out there,” and I went out there and we were all pushing each other and helping each other do intervals, and it was a lot of fun, and I’m really glad I went. And if I hadn’t… We hadn’t emailed each other the night before saying, “Hey, we’re gonna all meet this morning at 8 o’clock,” I probably wouldn’t have been out there, but I’m really glad I did it.

‘Cause that kind of forced me to go, and then when I was there it gave all the feedback and encouragement that I needed to haul my body around the track, and it was a good thing. There’s lots of ways to do that, go dancing, or meet a friend for a walk, or a game of soccer or whatever it is that you like to do. There’s tons of ways to do it, but making it social is one of many ways, but I think it’s the most basic, simple and fundamental way to help make exercise both necessary and fun.

Brett McKay: Never underestimate peer pressure.

Daniel Lieberman: Absolutely. Peer pressure is great.

Brett McKay: Use it for good. But use it for positive stuff. Alright. Well Daniel, this has been a great conversation. Where can people go to learn more about the book and your work?

Daniel Lieberman: Well, so we have a website. If you just Google me you can find me quickly. My lab has a website with lots of information, and Penguin Random House has a website for the book and… Yeah, it shouldn’t be too hard to find me and find more information. But of course, it’s all in the book.

Brett McKay: Fantastic, Well Daniel Lieberman and thanks for your time, it’s been a pleasure.

Daniel Lieberman: Oh, it’s been my pleasure. Thanks for asking me.

Brett McKay: My guest today was Daniel Lieberman. He’s the author of the book Exercised, it’s available on and book stores everywhere. You can check out our show notes at, where you can find links to resources where you can delve deeper into this topic. Well, that wraps up another edition of The AOM podcast. Check out our website at, where you can find our podcast archives as well as thousands of articles written over the years. And if you’d like to enjoy ad-free episodes of the AOM podcasts, you can do so on Stitcher Premium. Head over to, sign up, use code MANLINESS at check out for a free month trial. Once you’re signed up, download the Stitcher app on Android or iOS and you can start enjoying ad-free episodes of the AOM podcast. And if you haven’t done so already, I’d appreciate if you take one minute to give us a review on Apple Podcast or Stitcher, it helps out a lot. And if you’ve done that already, thank you. Please consider sharing the show with a friend or family member who you think will get something out of it. As always, thank you for the continued support. Until next time, this is Brett McKay reminding you to not only listen to AoM podcast but put what you’ve heard into action.

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