BITESIZE | What Hunter-Gatherers Can Teach Us About Movement, Exercise and Ageing Well | Professor Daniel Lieberman #624

0:00Dr. Rangan Chatterjee:Today's Bite Size episode is sponsored by AG1, a daily health drink that has been in my own life for over seven years. Now, this is the time of year when our immune systems are under the most pressure. It's natural to look for extra ways to support our immune defenses. But most people don't want to juggle multiple pills. They want something simple, effective and easy to stick with. AG1 is a daily health drink that provides key immunity supporting nutrients, vitamin C, vitamin A, zinc and selenium, all of which contribute to the normal function of the immune system. These nutrients are included in highly bioavailable forms, meaning they are much easier for the body to absorb and use.

0:50Dr. Rangan Chatterjee:And the best thing, of course, is that all this goodness comes in one convenient, tasty daily serving. For a limited time only, get a free AG1 flavor sampler and AGZ sampler to try all the flavors, plus free vitamin D3 and K2 and AG1 welcome kit with your first AG1 subscription order. That's$87 in free gifts for first-time subscribers. See all details at drinkag1.com forward slash live more. Welcome to Feel Better Live More Bite Size, your weekly dose of positivity and optimism to get you ready for the weekend. Today's clip is from episode 514 of the podcast with Professor Daniel Lieberman. Daniel is the author of the brilliant book, Exercised, why something we never evolved to do is healthy and rewarding.

1:52Dr. Rangan Chatterjee:In this clip, he reveals a fascinating truth. We didn't evolve to exercise, but movement is key to living well. He challenges some common beliefs that exist around exercise and shares simple ways of building sustainable movement habits into our daily lives. Everyone listening, I'm sure, has been hammered with the message that exercise, that physical activity is good for us, it's good for your body, it's good for your brain, it's good for your longevity, etc, etc, etc. etc so we've all got the knowledge that we possibly probably should be moving more yet despite having that knowledge so many of us are simply unable to put that into action regularly and they start to blame themselves they feel guilty which is a huge problem that i see and have seen in practice for many years so i wanted to start with this apparent paradox this idea that exercise is something that is really, really good for us on so many levels, yet at the same time, it's not necessarily something that we have evolved to want to do.

3:06Professor Daniel Lieberman:Oh, I would say we didn't evolve to do it at all. But yeah, that paradox is what really motivated my last book, Exercise. And maybe to answer your question, I'll give an anecdote, right? I was in Mexico doing some research and we were studying, you know, runners and people who run and actually discovered that most of the taro mara famous for running don't actually run very much. But anyway, there was this one elder fellow who was a famous runner to these very long distance races. And I was being a good anthropologist and I was asking all kinds of questions. And one of the questions was about training.

3:38Professor Daniel Lieberman:And, you know, I was beginning to realize that my concept of training was kind of alien to the taro mara. And this guy just looked at me and I could tell without even the translator saying anything, it's like, why would anybody run if they didn't have to? And I suddenly had this like, you know, this little epiphany, right? That our concept of exercise is alien to most people, right? And of course I work in parts of the world where people are very physically active. They work hard. Here I was in a part of the world where people are hardworking farmers. They've got no machines. They've got no running water.

4:11Professor Daniel Lieberman:They've got, you know, they're doing everything by hand. They occasionally do these long distance races, which by the way are a form of prayer. That's why they do them. But the idea of going for a five mile run in the morning is nuts. Nobody does that. And I had this moment that, yes, we evolved to be physically active, but the kind of what we call exercise, which I define as voluntary, discretional physical activity, it's planned for the sake of health and fitness, is a completely modern idea. And furthermore, if you're struggling, if you're a farmer or a hunter gatherer, of course we were hunter gatherers for most of our existence.

4:45Professor Daniel Lieberman:If you're struggling to get enough energy, right? Struggling to feed your family, going for a five mile run in the morning, which is about 500 calories, is a terrible idea, right? Because those 500 calories is energy that you could use either on your own body or on your family, right? So the idea of doing unnecessary, voluntary physical activity for no reason other than for your health and fitness when you're already very physically active is nuts. So we evolved to avoid physical activity except for two reasons, when it's necessary or when it's rewarding, right? So play is important and rewarding.

5:26Professor Daniel Lieberman:Work is rewarding. A race might be rewarding. But getting on a treadmill in the morning in a gym, you know, with fluorescent lights in a room with no air, et cetera, working as hard as you can, getting absolutely nowhere. There's a reason people dislike it. We never evolved to do that.

5:44Dr. Rangan Chatterjee:Yeah, I think that's a very powerful message today. And, you know, we're having this conversation in London. I'm rarely in London these days, but I came last week for a couple of days. And I think the underground station where I took a photo and posted on social media really illustrated your point, which was this beautiful flight of stairs. And on one side was an escalator going down, the other side an escalator going up. and literally there was nobody on the stairs and both sides of the escalators were full. And I posted it not, and the first thing I said is, this is not a post about blame, but I thought it just beautifully illustrated the problem that we have in modern society, which is why would you choose to take the stairs if you don't have to?

6:32Professor Daniel Lieberman:Of course, it's an instinct to take the escalator. There are no escalators in the Stone Age. I think I can say that with definitive knowledge, right? There are actually a series of papers that have been now done in many different countries. And it doesn't matter where you are on the planet, when there's a staircase next to an escalator, only less than 5 % of people take the staircase. And it doesn't matter what culture you are, it's a universal. Because it's an instinct to, if you can save energy, why wouldn't you, right?

7:00Dr. Rangan Chatterjee:And I imagine that our hunter-gatherer ancestors would also have taken the escalator had that option been available to them.

7:11Professor Daniel Lieberman:Of course. And I think in addition to the fact that it's an instinct not to exercise, right, not to be physically active when it's neither necessary nor rewarding, that we also engage in this form of blame or shame, right? and you have to remember that we're asking people to overcome a very deep-seated instinct right and then people feel bad about themselves because they feel that sure I mean they wake up in the morning and they think well yeah I should go for a run or I should do this or I should lift some weights or something and they don't do it for one reason or another and then they feel really bad right and then they think that well they're lazy there's something wrong with them they're actually normal right they're completely normal human beings and we I think our job is to try to figure out how to help people be physically active to maybe not even exercise, but how to be physically active in a way that, um, that doesn't cause that kind of, you know, do it in a positive way rather than a negative way.

8:06Professor Daniel Lieberman:And, and I think, and no offense, I know because you're a physician, but you're a physician that cares seriously about prevention. But I think one of the problems is that we've medicalized exercise. We consider it a pill, right? And nobody likes to take pills. Nobody likes to, you know, it doesn't make it fun. It doesn't solve that particular problem of overcoming that barrier. I mean, I'm sure you know that most medications, people don't take their medications either. So if people don't take their pills for diabetes or this, that, or the other, why are they going to take the exercise pill?

8:37Dr. Rangan Chatterjee:Yeah. So perhaps a new PR angle is needed around exercise. Because it's often called the magic pill, isn't it? exercise and, you know, anti-cancer, anti-aging, anti-mental health problems, anti-everything.

8:50Professor Daniel Lieberman:And I think we have this idea that you have to swim the English Channel or run a marathon or do a full triathlon, you know, Ironman, etc. Absolutely not necessary. Again, some exercise is better than none, more is generally better, but the benefits tail off. It's interesting that the movements that, you know, our ancestors used to do regularly,

9:11Dr. Rangan Chatterjee:and you've detailed them in depth in exercised, but they're not doing those things for the purpose of health and wellbeing. Like that's a byproduct of doing what they need to do in order to survive, right? So it's a side effect.

9:31Professor Daniel Lieberman:So it is a side, I mean, you're right. They do it because they have to, right? If you want to have dinner that day, you have to go out, you have to be physically active to get food, right? There's no Uber Eats in the Paleolithic, right? So it's true. Physical activity was absolutely necessary. But I think that it's not just a side effect. I would argue that human beings, not only like every other animal, benefit from being physically active, but there was special selection in human evolution for exercise to be unusually potent for enabling us to live long and healthy lives. And that's something that makes us different from every other organism.

10:09Professor Daniel Lieberman:So to understand that, you have to recognize that we evolved from apes, right? Our closest living relatives are chimpanzees. And you know those shows on TV where you watch chimpanzees and they're doing all kinds of amazing, wonderful things. They do that, but very rarely. Most of the time, chimpanzees just sit and eat. And then occasionally do some wild, crazy things, have sex, run around, throw things, and then they go back to eating and digesting. And so chimpanzees turn out to be basically couch potatoes. They're incredibly inactive. Typical chimpanzee walks two to three kilometers a day, takes basically as many steps per day as a sedentary American, sleeps 12 hours a night, and that's kind of a chimpanzee life.

10:48And then we evolved for two things that are very special in this regard.

10:54Professor Daniel Lieberman:One is that we evolved to be way more physically active. So we've got data on hunter-gatherers and systems as farmers. These people are taking 15 ,000 to 20 ,000 steps a day. They're running, they're carrying, they're climbing, they're doing all kinds of things. So we evolved to be extra active compared to our ape ancestors. That's one thing. But the other thing that's important is that we also evolved to live very long lives after we stop reproducing. So almost every species on the planet stops, you know, basically doesn't last very long after they stop reproducing. That's because natural selection, sadly, cares about only one thing, and that's how many offspring we have, right?

11:31Professor Daniel Lieberman:So once you stop having offspring, you enter what's called the selective shadow. I love that term, right? It means that you're basically irrelevant, right? There's no selection to keep you alive after you stop having babies. And humans are one of very few species for which that's an exception. And that's because human grandparents actually play an important role in helping their children and their grandchildren. And what are they doing? Well, I mean, they're passing on knowledge and all that sort of thing, but they're also hunting and gathering. They're foraging. Grandparents in hunter-gatherer societies are out there every day.

12:04Professor Daniel Lieberman:Grandmothers are digging up tubers. and other sorts of things and bringing them back for their children and their grandchildren. Grandfathers are out there hunting and bringing back honey and all sorts of things like that. They're physically active. And so we evolved to live long lives, not retiring, going to the beach and playing canasta or whatever it is. We evolved to live long lives to be physically active. And in turn, I believe that there's been selection in our evolutionary history for the effects of that physical activity to turn on the mechanisms in our body that help us increase our health span, which means increases our lifespan.

12:42Professor Daniel Lieberman:So physical activity isn't just something you do to get the food, it is. But the reason exercise or physical activity is so healthy is that we've undergone selection for that physical activity to turn on all kinds of repair and maintenance mechanisms that keep us healthy. and because we never evolved not to be physically active, we never evolved to turn them on to the same extent when we're inactive. So instead of thinking of exercise as medicine, I would think of inactivity as being like poison or like not having air.

13:12Dr. Rangan Chatterjee:Yeah, so it's not necessarily that exercise or physical activity is good for us. It's that the lack of doing it is really harmful.

13:23Professor Daniel Lieberman:Exactly. We call that a mismatch in evolution. It's an evolutionary mismatch. Just like we never evolved not to breathe, right? That's a problem, right? We never evolved not to be physically active. And when we stop being physically active, everything goes wrong. I mean, literally, because physical activity affects every system in our body.

13:40Dr. Rangan Chatterjee:Yeah, it's so fascinating where you were even writing about how a nursing mother, yes, she still does some gathering, I think, but you were sort of making the case that the grandmas are way more active. I thought that was really, really interesting, because that's quite alien to the common belief, I would say, certainly in Western cultures that you can kind of slow down a bit as you get older and we have this modern phenomena that's retirement, right? Yeah.

14:10Professor Daniel Lieberman:They're digging, they're carrying, they're walking. This is what you do. And it's rewarding, of course, but it's also necessary. And I think in turn, that physical activity helps them live to be grandparents in the first place. Think about it this way. In the West today, a lot of people as they get older become less active. We know that from lots and lots of studies. And we don't turn on those repair and maintenance mechanisms that keep us healthy. So we're more likely to get heart disease and diabetes and osteoporosis and Alzheimer's and the list of various diseases is very long. But now we have medicine, people like you, kind of keep them going, right?

14:51Professor Daniel Lieberman:And so we can enable us to live. we have reasonably long lifespans, even with a lot of chronic disease. So the average American, I think their lifespan is 78, 79. The average health span, the number of years that the average American lives without entering a period of chronic disability is about 60 something, 63. So the average American spends 16 years before they die in a state of chronic disease.

15:17Dr. Rangan Chatterjee:Yeah. In terms of walking, um there's a you know maximism there that we should aim to have around 10 000 steps per day

15:27Professor Daniel Lieberman:what's your take on that oh well you know that's a kind of a funny story i'm not sure if you've covered that on this on your podcast before but you know that 10 000 steps a day came from there was this accelerometer that was created for the in japan just before the olympics uh in 64 and i The story is that apparently in this company, they were sitting around the table and deciding what to call it. And apparently 10 ,000 is an auspicious number in Japanese. And they said, well, let's call it the 10 ,000 steps meter. And it turns out it's actually not that bad, right? It's a, you know - It's not bad as a recommendation, I think.

16:04Professor Daniel Lieberman:I mean, you know, it turns out to be okay. So if that'll help you get more steps in, so, you know, if you have one of those watches that makes sure you get 10 ,000 steps every day, fine. But we've, again, we've kind of medicalized it, right? We've turned it into a prescription. And we often talk about optimizing health or whatever. Well, it doesn't work that way, right? If you look at, so my colleague, Ayman Lee at Harvard has done a lot of work on step counts in health. And if you look at some of the graphs that she's published, for example, first of all, there's a lot of error around the mean, but if you're interested in say heart disease, the more steps you take, the better.

16:45Professor Daniel Lieberman:3 ,000 steps is better than 0 ,000 steps and 5 ,000 steps is better than 3 ,000 steps. Is there an upper limit? So far, I don't think she sees a limit. This is for steps. It's just walking, right?

16:55Dr. Rangan Chatterjee:So like if you could get to 15 ,000 or 20 ,000 steps, it's currently from what we know, we think that's going to help decrease your risk of heart disease.

17:03Professor Daniel Lieberman:That's what her data show. But again, there's a lot of variation around the mean. So your benefit might not be the same as my benefit. Of course. But if you look at the data on step counts and say all cause mortality, it kind of evens out starting around 7 ,000 steps.

17:19Dr. Rangan Chatterjee:So once you're hitting 7 ,000 steps a day, it's kind of like, look, you've got most of the benefits.

17:25Professor Daniel Lieberman:Yeah. And if you did diabetes, you'd get a different curve, et cetera, et cetera. But again, there's a mean, but there's also incredible variance around the mean. So what might be good for you is not gonna be the same thing as for me or if you're 50 versus if you're 20 or if you've had knee injury or I could go on, right? So we prescribe it like how many aspirin you should take or how many milligrams of such and such you should take. And it doesn't work that way, right? So maybe that helps some people, but I think other people, it makes them confused and agitated and stressed, right? It's yet another source of stress in their life.

17:59Dr. Rangan Chatterjee:Did you say before that some of these hunter-gatherer populations that you have studied, they're taking what, 15 to 20 ,000 steps a day-ish?

18:08Professor Daniel Lieberman:Yeah, but again, that doesn't mean that that's best for them, right? Just because hunter-gatherers do something doesn't mean we should do it. It's not a prescription, right? Instead, these are populations that tell us about the normal range of human variation and how our world has changed, enabling us to now understand what's a mismatch, right? What is it that we're not adapted for, right? Because a mismatched disease is a disease that is more common or more severe because our bodies are inadequately or imperfectly adapted for this novel environment. And so these are ways of helping us identify the mismatches in our world and then addressing them.

18:46Professor Daniel Lieberman:So there is no one number of steps to take per day. Look, the evidence on exercise is pretty darn clear, right? Which is that, or physical activity, I should say, right? If anything is better than nothing, right? If you're completely sedentary, just taking a few steps, you know, more steps a day, climbing the stairs, you know, parking your car further away from the shopping. anything is better than nothing. More is better. And at a certain point, the benefits seem to tail off, right? But trying to come up with a number, an optimum is not only impossible, I think it actually sends an incorrect message, right?

19:28Professor Daniel Lieberman:That it's like a medicine which you can prescribe in a particular dose. It just doesn't work that way. And I think, and we also get this idea, it's like this magic pill, right? I mean, exercise is good for you. There's no question about it. Physical activity is good for you because if you don't do it, it's bad for you, but it won't prevent all disease. It decreases your vulnerability. So people who are physically active are much less likely to get heart disease. They're much less likely to get diabetes, but they're not prevented from getting them. You can still get diabetes if you exercise. You can still get heart disease if you exercise.