Exercise myths busted: Practical steps to sustain your health

Admit it, exercise isn't everyone's favorite pastime. Of course, our ancestors weren't hitting the gym by choice — our evolution has wired us to stay active, and this natural activity actually slows down the aging process.

The good news is that you can achieve the benefits without feeling like you're "exercising."

Daniel Lieberman is a paleoanthropologist at Harvard University. He’s the Edwin M. Lerner II Professor of Biological Sciences and a professor in the Department of Human Evolutionary Biology. He’s best known for his research on the evolution of the human mind and the human body.

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Transcript

[00:01:35] Jonathan Wolf: Daniel, thank you for joining me today. 

[00:01:37] Daniel Lieberman: My pleasure. 

[00:01:38] Jonathan Wolf: And it's fun to do this in person. Now, we have a tradition that we always do on this show: We start with a quickfire round of questions, which in general, professors don't love because the rules are that you can say yes or no — or if you have to, give a one-sentence answer. Are you willing to give it a go? 

[00:01:55] Daniel Lieberman: Let's try. 

[00:01:56] Jonathan Wolf: Alright. Did our ancestors exercise? 

[00:02:00] Daniel Lieberman: No. 

[00:02:01] Jonathan Wolf: Is sitting bad for us? 

[00:02:04] Daniel Lieberman: No. 

[00:02:04] Jonathan Wolf: Is it normal to dislike exercise? 

[00:02:07] Daniel Lieberman: Yes. 

[00:02:08] Jonathan Wolf: Do we need to do 10,000 steps per day? 

[00:02:11] Daniel Lieberman: Eh, not sure. 

[00:02:13] Jonathan Wolf: Okay. And lastly, can someone start exercising late in life and still benefit? 

[00:02:18] Daniel Lieberman: Absolutely. 

[00:02:20] Jonathan Wolf: That wasn't so bad, was it? 


So I have one that you can have a whole sentence for. What's the biggest myth about exercise that you've discovered through your research? 


[00:02:29] Daniel Lieberman: Well, I think it's the one that you just asked. Which is this idea that it's sort of normal as you get older to be less active. And I think of all the myths that I've been interested in, that one is not only, I think that it surprises me just how much people think it's just normal to become less active as they get older, but also people don't understand just how important it is to stay active as you get older. 


You know, for a thousand reasons, not the least of which is your mental health and your physical health. 

[00:02:57] Jonathan Wolf: Hi, I hope you're enjoying the show so far and learning a lot about why what you thought about exercise might not entirely be true. 

Now, if you're not already a regular listener, I hope you feel like you might come back. It would mean a lot to me if you hit the subscribe button, so you know whenever a new episode arrives. This podcast is an ad-free labor of love, sustained by people like you choosing to listen to us. 

Okay, back to the show. 

I thought I was brought up with these stories that, you know, if we were living, you know, in the African savannah, then the young people ran around and like, killed the wildebeest and the hunting and the old people sat around at home, but they were wise and old and that was sort of their job. 
So I think that is definitely the... you're laughing, but I think that's very much the story that I was brought up with. 

[00:03:43] Daniel Lieberman: Yeah. Kind of the Rudyard Kipling view of human behavior.  


[00:03:47] Jonathan Wolf: I'm worried now that I have the Rudyard Kipling view, that doesn't sound good. But that is, I think that is sort of the idea that you were old and that the value of surviving was your wisdom. Of course, you wouldn't do anything physical. You'd just sort of, you know, be supported by these young,
strong people. 

[00:04:00] Daniel Lieberman: Well, wisdom is important, and that's certainly one of the values of getting old and for sure, wisdom that elders impart to youngers is important, but they also work hard. 


[00:04:11] Jonathan Wolf: I think that's really interesting. And I really enjoyed the book, which I was reading on the plane over, and it made me think about exercise quite a bit. And, for me, exercise is definitely a chore. 

So I work out two to three times a week because I've been convinced by a whole variety of scientists that, you know, this is really important for my health. But it's definitely not fun, and the pleasure I take in it is at the point that it's done. I'm like, oh, I feel really good that I've now done it. But I'm definitely not taking a lot of pleasure during the period of, you know, lifting these weights. And, you know, I know that's one of the things you talk about in this book, along with a whole series of other myths. So I'm really looking forward to digging into that. 

Before we talk about how we sort of learn from our ancestors and how, you know, your own research has looked at both like what they might've done in the past and modern hunter gatherers though, I'd love to start actually with just a really simple question. So is exercise good for us? And if so, why do most of us hate it?  


[00:05:16] Daniel Lieberman: Well, to answer that question, let's start with a definition. All right. So exercise is a form of physical activity. So physical activity is just moving, right? You know, climbing the stairs to get to my office, you know, making breakfast, whatever. 


That's all forms of physical activity. And exercise is a special form of physical activity, which is discretionary, voluntary physical activity that we do for the sake of health and fitness. 


[00:05:39] Jonathan Wolf: Rather than because I need to get to the top of the house in order to pick something up.  


[00:05:43] Daniel Lieberman: Yeah. And if you think about exercise that way, and actually exercise comes from the Latin word that, you know, has to do with hoeing, you know.

There's a reason when we, you know, you do your maths exercises, right? We call them exercises. You're not using anything other than your brain there. Right. But it's a modern behavior, right? 

Nobody until very recently exercised sort of for discretionary, voluntary reasons for the sake of health and fitness.

[00:06:05] Jonathan Wolf:  Is that
right? You say that as if it's obvious, but weren't, there weren't lots of people doing exercises in the Roman times or the…

[00:06:11] Daniel Lieberman: Well, that's still recent as far as I'm concerned, right? 


[00:06:14] Jonathan Wolf: So for the, your idea of recent is longer than mine. 

[00:06:18] Daniel Lieberman: Yeah. I mean, I'm talking prehistory, right? For millions and millions of years, people were physically active for two reasons and two reasons only. When it was necessary, in other words, in order to get food or to avoid being somebody else's food, right? 
Or when it was rewarding. Think about play. I mean, children in all cultures play. Adults play. And play, of course, is very useful for all kinds of reasons.  


[00:06:38] Jonathan Wolf: But our ancestors were not doing exercise in order to make sure that when they went hunting they would be successful. 

[00:06:44] Daniel Lieberman: No, never.  Um, so...  


[00:06:45] Jonathan Wolf: Again, you say that, but that's really interesting because we think now, well we think you need to do lots of exercise in order to go and be successful at, you know, if you were gonna be going to have to run in a race, you think, well, you need to do lots of exercise in order to be successful at the race. But our ancestors didn't need to do that in order to catch the antelope.  


[00:07:04] Daniel Lieberman: No, because. Yeah, I mean, there's many ways to answer that question. But let me just say that the reason I started this book, actually, they're really sometimes, you know, people make up these epiphanies, right? But I actually really had one when I was doing some research in northern Mexico, studying a Native American population that's famous for its running, the Tarahumara. 


And I was collecting data, I was being a good anthropologist, had my clipboard with all my questions that I'd worked out in advance and talked to ethnographer friends to make sure that I was doing it in the right proper way when I was measuring their feet and measuring their running biomechanics and doing all kinds of stuff. 


Just me and a guy who I'd hired to help me travel around and we were sleeping on the floors of Pueblos and all this sort of stuff. Whenever I asked people about training, that's what you're talking about, I got these really like, confused answers, right? People didn't understand the question. And I had a translator. 


And finally, there was this one old guy I was interviewing. I'll remember him intensely. And he was a shaman, famous for his long distance running too. And so I could tell my translator was asking my usual question. You know, how do you train for running? And he looked at me, and I didn't even need a translator, and I could say like, why would anybody run if they didn't have to? 


And that's, that's what he said. And, you know, this is a guy who runs like hundred mile races, right? He doesn't train. His life is his training. He's very physically active. He walks long distances. Occasionally when he was young, he used to run in order to hunt. But the idea of getting up in the morning, like this morning I ran about 5 or 6 miles, right? 


just for the sake of running 5 or 6 miles. 

The various places I go to do research, and when I run in the morning, they laugh at me. They think it's hilarious. And it makes sense because most people in most parts of the world, for most of our evolutionary history, struggled to get enough food, right? 


It was hard, right? And I spent, what, about 500 calories this morning running my 5 miles. If you're struggling to get enough calories, wasting 500 calories in the morning, just for no purpose whatsoever, is a really, you know, it's not a good idea. It's maladaptive. 

Playing, on the other hand, when you're a child, you learn skills, you develop capacity, you learn social skills. There's all kinds of good things that come out of play. And play, and adults continue to do that. But play is kind of a special form of physical activity. I don't think of play as exercise. It doesn't at least fit my definition of exercise.  


[00:09:19] Jonathan Wolf: And so does that mean that just the normal lives that our ancestors would have lived was in essence, sort of all the training they required in order to then be able to do that run or chase or whatever. 
So they didn't need to do exercise because just their normal life was providing the necessary training.  


[00:09:41] Daniel Lieberman: Yes, they were very physically active, right? And physical activity promotes a response by your body, which not only, you know, improves or maintains your performance ability, but also has all kinds of health benefits. 


You know, the average hunter gatherer walks 10 to 15 kilometers every day, every single day. No, there are no weekends, there's no holidays, there's no retirement, there's nothing. They do it day in, day out for their whole lives. And they're often digging, sometimes they have to run, they have to climb trees, they have to lift things, you know. Their lives involve a reasonable amount, not a huge amount, but a reasonable amount of physical activity. 


And that gets them basically just enough calories to make it to the next day. And they occasionally do things for fun that are physical. They dance. But dancing, of course, is very important for helping you find a mate and having fun and for social reasons. Again, it's fun, right? Yeah. But no hunter gatherer I've ever met or heard of or seen of in the ethnographic literature has ever gone to find some rocks and then just
simply lift them. 


[00:10:46] Jonathan Wolf: Lift them in order to be strong enough for their other tasks.  


[00:10:49] Daniel Lieberman: Yeah, or go for a 5 mile run in the morning, whatever. That's just, it's inconceivable.  


[00:10:55] Jonathan Wolf: I love that because it's definitely at odds with, I think, a lot of what people think. Maybe that helps to answer, I guess, the second part of my question, which is, if this exercise, because you also said exercise is good for us, I then was like, so why do most of us hate it? 
Does this tie into the fact that actually, historically, we never needed to do the exercise? 

[00:11:15] Daniel Lieberman: Yeah, well, I mean, again, remember, it's physical activity that's good for us. Exercise is a kind of physical activity. But if you're a, you know, a postman and you walk around, you know, delivering mail, that's physical activity, it's not exercise. And it's good for them. 

One of the very famous early studies, actually the first major study to show that physical activity is good for your health was done in London on bus conductors. And compared the bus conductors, you know, the people who walked up and down the bus collecting tickets. 

[00:11:45] Jonathan Wolf: Which is definitely a long time ago because that's been one of them for a long time. 


[00:11:46] Daniel Lieberman: I remember when I was a child going on buses in London and there was this man with this little thing that used to do that, right? And then there was the driver, right? And the driver sat in a seat all day long driving the bus. And the rate of heart attacks in the drivers was twice that of the conductors. 


[00:12:01] Jonathan Wolf: Twice. And the only difference was the bus driver was sitting down all day and the conductor was walking around. 

[00:12:07] Daniel Lieberman: Was walking around. And then there was a follow up study because they thought, well, okay, maybe drivers are really stressed because they have to deal with London traffic. So they compared postal workers in London with the people who worked in the post office who managed them, the administrators, right? 


And again, exactly the same result, right? So that was the, that was back in the 1950s, right? And since then, of course we've had, I couldn't even count the number of studies which show how important physical activity is for health. But again, that's physical activity, not exercise. 

But if you're already a very physically active person, and you don't need that much physical activity for your, for the benefits, just a moderate amount is more than sufficient really to promote health. 
And you're struggling to get enough food, which is what the case was for hunter gatherers, and most subsistence farmers. The people I work with in Africa, for example, are struggling to get enough food. Going, you know, running, like I run maybe 30 to 50 miles a week. That's, you know, that's a lot of calories, and if you're stressed for calories, that's a really bad idea.
I mean, that's a, you're actually putting your family at risk. 

So when people say they hate to exercise, it's because we're asking people to do something that is intrinsically unnatural. And the example I love to point out is if you ever go to an airport, or a mall, or a subway stop, or whatever, where there's an escalator next to a stairway. 
I was just in the subway here in Boston, going up to South Station, and I got off the subway car, and everybody filed and waited in line to go up the escalator. And I was one of the few people who took the stairs, because I have to, otherwise I'm a hypocrite, right? 

[00:13:42] Jonathan Wolf: And did you take the stairs because you know it's good for you, but you hate doing it anyway? 
Or are you in this exception for some reason? 

[00:13:48] Daniel Lieberman: No, I don't like taking the stairs. But if anybody, you know, I'm Mr. You Should Be Physically Active. If anybody catches me on the escalator, I'm in trouble, right?  


[00:13:55] Jonathan Wolf: So you're in the same world as me. It’s not that you enjoy it, you're just trying to override your natural tendency to basically be lazy and not do this. 


[00:14:03] Daniel Lieberman:  Just like, you know, most people, if you put a piece of cake in front of me and an apple, right, I'm going to want the cake, right? And I have to override my instincts to eat the cake rather than the apple. And if nobody's looking, I might have the cake, right?  


[00:14:17] Jonathan Wolf: And I do sometimes meet people who seem to really enjoy exercise. And they do, like, these extreme things like Ironman or ultramarathons or all the rest of it. So are you saying that they're just a bit weird, which I've always suspected, or... 

[00:14:34] Daniel Lieberman: Well, I think it's more complicated than that. I mean, I enjoy... I usually rarely enjoy starting exercise. But I usually am glad I've done it when it's over. And that's what you mentioned at the beginning, right? 

So, I mean, this morning was no exception, right? There was a beautiful morning here in Boston, it was perfect weather, could not have been nicer for running. And I was like dithering and complaining, and finally my wife said, come on, just go. 
Time for you to go. And you know, I didn't enjoy the first mile very much, I never do. But then I settled in and I enjoyed myself. And by the time I came home, I was glad I did it. 

But I've done it enough to know that I get some benefit and I'm reasonably fit and that it's not a horrible chore, right? 
But if I'm unfit and struggling to exercise, right, if I'm overweight or, or haven't exercised in a long time, it's hard. And we shouldn't make people feel bad for not liking it, because it's actually normal. And we shouldn't make people feel bad for feeling like they, you know, being inhibited or you know, you have to overcome some inertia. 

[00:15:38] Jonathan Wolf: And you're saying that is deeply rooted in us. It's actually our body has sort of evolved to protect those calories, you know, protect our calories, not waste energy on doing this exercise. 

So, you know whenever you do do this exercise, you sort of, you deserve a big round of applause is what I'm hearing, like, you're sort of overcoming something that is actually natural to say, well don't waste your energy doing this, because after all, if you really needed to do this. You'd go and do it anyway because you won't get any food or whatever. So at which point, you wouldn't need this strong desire to do exercise, you'd just be like, well I have to go and walk that far in order to get this food, otherwise I'm going to go hungry and that is definitely worse. 


[00:16:16] Daniel Lieberman: Well I mean, I think you've made it more complicated than necessary. 

I mean, again, just to simplify it, it's not really complicated, right? We evolved to be physically active for two reasons and two reasons only, full stop. When it was necessary or rewarding. And so if we want to help people exercise, we have to either make it necessary or rewarding or both. 

So if I'm going to meet a friend for a run, I don't necessarily even think about it as exercise. Yeah. I'm going to go meet my friend Elena, which I do every Friday morning and we run together. And it's fun. We chat about the week and this, what's that, et cetera. And I don't think about it so much as exercise, it's my, you know, weekly meeting with my friend and neighbor Elena. 

Or maybe I have a coach, right? And my coach says, Hey, you're training for the Boston Marathon on Tuesday, I want you to do this. He's kind of made it necessary for me, right, and I've signed up for this race and I better damn well train. 
Otherwise I'm going to be humiliated or have a horrible time. 

So we use carrots, we use sticks, but it's really very simple, you know, we evolved to be physically active either because it's necessary or rewarding. 

Now we live in this world where people know that it's good for them to be physically active, aka exercise, because they don't otherwise, you know, they sit in chairs all day long. 


And either they somehow have the willpower to overcome that, that distaste for what they're doing, or they find ways to make it fun. 

[00:17:35] Jonathan Wolf: That's
brilliant. So one way is that suddenly instead of this being unpleasant, there's this way that switches it to being fun. And actually, you talk about dancing in the book, and I was sort of struck by that, that in my mind, I enjoy dancing. 


That's definitely not exercise. That's fun. And then you point out, well, actually, it's quite a lot of exercise really, but because you switch to think, you don't think about it like that. It's just fun. And therefore you just respond to it in a different way. 


[00:17:57] Daniel Lieberman: Yeah. I mean, the Tarahumara I was mentioning earlier. 


are famous for their endurance dancing. And people, everybody talks about their endurance running. They have dances, I've been there. I can't keep up with them and they'll dance for 24 hours. Yes. 

They just go on and on and on and on. There's a lot of drinking going on. It's a party. They're having a great time, right. And that of course is obviously training, right? Of course it's not, they don't think of it as training and of course it helps them because dancing is jumping, and running is actually just jumping from one leg to another.  


[00:18:29] Jonathan Wolf: That's really interesting. Now, you've already touched on a few of these, but I really wanted to ask, you know, you've visited a lot of these sort of remote tribes around the world, to understand sort of how they live their lives. 


And I guess, could you help our listeners to understand, like, why do you do that? And what does it help us to understand? 

[00:18:56] Daniel Lieberman: Well, you know,
I think it's normal to think that your life is normal, right? 

[00:19:00] Jonathan Wolf: Yep. As a child, that's absolutely how we all think, isn't it? 
  


[00:19:02] Daniel Lieberman: Sure, I mean, I think it's normal to get in this metal box and travel across the city and get in a metal tube and fly around from one continent to another and eat breakfast cereal that comes in a box. We could go on and talk about all the very modern things that we think are normal, but we didn't evolve that way, right? 


We evolved to be hunter gatherers for almost our entire evolutionary history, we're hunter gatherers. And then for thousands of years, we were subsistence farmers before the industrial era. 

And if you want to understand how bodies work, and how physical activity and diet and all these things, you know, affect us, you can't just study people in Cambridge, Massachusetts, or London, or, you know, Toronto, or where you. You have to go out into the rest of the world, which is how people act. 


Other people use their bodies, right? There's a colleague of mine, Joe Henrick, who's written this wonderful paper called The Weirdest People in the World. Weird, for him, is Western, educated, industrialized, rich, and democratic. It's actually only about 10 percent of the world fits that category. 

A colleague of mine actually did a study where we showed that over 90 percent or approximately 90 percent of all the biomedical data, psychological data, medical data comes from Europe and North America, a little bit of Australia. 
We're generalizing about human beings from a very tiny, unusual and frankly, weird sample.

So if you want to understand how and why we are the way we are, how our bodies evolved to work, what it's like to be physically active, how physical activity functions in aging. You have to, you can't just study people in the West, you need to travel elsewhere. 


And so that's why we do it. 

[00:20:41] Jonathan Wolf: It's interesting. We've covered on the podcast some scientists looking specifically at the gut microbiome and that's obviously something that ZOE's very interested in. And one of the things they talk about is sort of a bit similar to this, which is when you look at the gut microbiome of the people you're talking as weird people, so sort of westernized, post industrial, that this microbiome is incredibly shrunken compared to the microbiome that they see elsewhere. 


And it sounds like you're saying more broadly, in a sense, our whole lives and how we understand things. You're saying we need to step away from how we might be living in the West, because actually these sort of pre-industrialized environments are a much better way to understand really what is the way our bodies are built and how, what would really be healthy for us?


[00:21:27] Daniel Lieberman: Yeah. I'm gonna give you a simple example. Like, what did you carry today? 


[00:21:31] Jonathan Wolf: A small rucksack.  


[00:21:32] Daniel Lieberman: Exactly. So that's weird, right? I mean, in most populations, in most of the world, people spend much of their day carrying heavy things. They carry babies, they carry food. If they hunt an animal, they have to carry it back to camp. 
They carry water. 

I mean, if you and I want water, we just go and turn a little tap right out it comes, right? That's in, that's incredibly recent, right? If you lived in London just 150 years ago, you'd have to go to the local well and pump it, and then carry it back to your, you know, cholera filled water as well. Right? 

So, you know, We don't carry anything anymore, right? And so we think that how backs function, almost all the data we have about back biomechanics, is on people who sit in chairs all day long and never carry anything. And if you really want to understand how the back functions and how physical activity affects the back, you need to go to places like where I go, like for example, we were working in Rwanda this summer where people have to carry absolutely everything. 


[00:22:26] Jonathan Wolf:  It's really interesting. So what you're saying is what we think of as normal, which we just pick up from looking everybody around us, like it's normal not really to carry very much, is actually weirdly abnormal and not the way that our bodies are built or evolved, because actually it's never been like that until just very recently in a small part of the world.


[00:22:48] Daniel Lieberman: 
Yeah. To go to a supermarket, get a shopping cart. Put boxes of food in it, carry the, you know, shopping cart, then you might carry the bag to your car, and that's about it, right? That's all, everything about that from going to the supermarket to the way you carry foods around the supermarket, all of that is completely abnormal. 


[00:23:11] Jonathan Wolf: So, I've never been to any of these places and many of our listeners haven't, so what is it that is surprising that is different. Because there's some things that you know, we understand is obviously that that environment is quite different from ours. 

But the example you just gave is like, oh, I'd never thought about that. What is it that is sort of surprising, that you've taken away about how we lived versus...  


[00:23:34] Daniel Lieberman: I do not answer that question because there's so many things that are different about our world. 

I think actually what surprises me the most is how human beings are just human beings, right? People are lazy everywhere. People are... you know, jealousies and whatever. 

We often tend to romanticize the past and you know, think about, ah, the good old times when we were farmers or hunter gatherers. And they have tough lives too. 

I mean, I think the more I've traveled around the world and work and live with other cultures, the more I realize how, you know, scratch underneath the surface, there are many things about humans that are the same. 

But also, of course, there are plenty of things that are very different. Our diet, of course, is very different. I mean, think about, like, after this interview, you're going to think, hmm, I'm hungry. What shall I have for dinner? Shall we have Italian? Or shall I get pizza? Or shall I go for Chinese food? Or a vegetarian restaurant? 

We just think it's normal to choose what you're going to eat. If you're a farmer or a hunter gatherer, you don't choose what you eat. You eat what you have, right? You eat what you grow. 

We think it's normal to, you know, wear shoes and to exercise and to sit in chairs all day long and to not carry things. 
I mean, I could go on. 

And many people are just surprised when I, you know, mention the water that like they're, they must know at some level, but they just haven't really thought about how our lives have been transformed by plumbing. 

[00:24:59] Jonathan Wolf: I think that's right. I think if you don't experience this, it's really interesting what you said. 

I'm still thinking about the carrying which is the bit I think that I'm really struck by because I think I'm so used to this idea that you don't really need to carry things around very much and that therefore you have to do exercise where you carry heavy iron weights around, because I've been told that's really important for my health. And you're just saying well you're only doing that because until very recently of course you'd be carrying lots of heavy things around just to function. So it's sort of like we're having to substitute these things that… would have just happened as part of our lives.


[00:25:29] Daniel Lieberman: You know what's even funnier? You probably actually spent money buying heavy iron things to carry them. That's right. I mean, that's hilarious, right? I mean, imagine explaining that to a hunter gatherer, right, or to your great great great great great grandparents who are farmers somewhere in England or wherever. They would think you're the silliest person on the planet.

[00:25:46] Jonathan Wolf:. I mean, I think just explaining it to my father, to be honest, thinks, I think he has the same attitude as the hunter gatherers you were describing about exercise. He's like, well, why would you do that if you don't have to? So I'm not sure I have to go that far back. 


I'd love to talk about some of the, sort of, therefore, the myths of exercise that come out of this. I think there's many different things that you've learned out of this experience, but it seems like one of the things that you've taken from a lot of these different people that you've been to, and I think a lot of other scientific literature, if I understand this. There are quite a few things that we say today about exercise that not only aren't well backed up by science, but might actually be completely myths. 

Where would you start? What's the thing that you would…  


[00:26:28] Daniel Lieberman: God, there's so many. It's hard to know. Well, I started the book off actually with, the first section of the book is on inactivity, because if you want to understand activity, you also need to understand inactivity. 


There's sort of two sides of the same coin. And I think one of the myths is that our ancestors were incredibly physically active. You know, they were built like Arnold Schwarzenegger and incredibly strong and incredibly fast and worked really hard and never sat in a chair ever and, you know, slept always eight hours and all that. 


All of that's false. So, first of all, our ancestors, our hunter gatherers, even farmers, are strong by many people's standards, but they're not super strong because, after all, muscle's expensive, right? If you build weights and lift weights to bulk up, you're going to add a lot of muscle mass, but muscle's a really expensive tissue. 


There's a reason we have this use it or lose it physiology, is that if you don't need it, you don't want to pay for the extra calories,
right? 

[00:27:25] Jonathan Wolf: You're saying that. As you increase the muscles, you need extra calories just to support those existing muscles.

[00:27:32] Daniel Lieberman: Yeah, you spend a good, you know, 30-40 percent of your metabolism just paying for your muscles. Just sitting there, not even using them. They're very expensive. 

[00:27:41] Jonathan Wolf: Just to sustain them in existence.  


[00:27:43] Daniel Lieberman: Yeah, they're expensive tissues. So you want enough, you want to be economical. You want enough but not too much, right? 

[00:27:50] Jonathan Wolf: Because if you have too much muscle and then you don't get any food, then you might end up dying. Is that what we're saying? 

[00:27:55] Daniel Lieberman: I mean, so the basic fundamental principle behind life is you eat food and then you have babies, right? That's the equation of life. Food in, babies out. That's all evolution actually cares about, which is kind of depressing, but nonetheless,  


[00:28:08] Jonathan Wolf: That's a little depressing. Okay. Keep going.  


[00:28:11] Daniel Lieberman: All organisms ultimately are about bringing in energy. using that energy to reproduce and create other versions of themselves. And we are, sadly, actually no different, right? 

But energy is a constrained, limited resource for most organisms, and was until recently, and it's still for many people today, still the case. 
So anytime you spend a calorie on running, you know, in the morning or paying for your unnecessary muscle, that's energy you're not spending on reproduction. 

We call this energy allocation theory, right? So spending energy that's on say, extra muscle that is then taking energy away from reproduction. And so we've long ago evolved a system to add muscle when we need it.  


[00:28:53] Jonathan Wolf: And when you say take away from reproduction, I think a lot of people are a bit confused. You don't literally mean having sex. You mean something much broader. Yeah.  


[00:29:00] Daniel Lieberman: Hormones. Right. You know, your testosterone levels or your estrogen levels, your progesterone levels, and, you know, energy that's allocated towards reproduction, exactly. 


Or, you know, nursing, you know, I mean, nursing, you know, is very expensive. 600 calories a day to produce breast milk. So we have all kinds of adaptations to add muscle when we need it. So that's, you know, working out. And then for atrophy to occur, to lose that muscle when we're not using it. 
And that's useful.  


[00:29:31] Jonathan Wolf: And that is why, again, just to make sure that we're all following. If we don't do this physical exercise, we see our muscles shrink. This is our evolution sort of protecting us and saying, well you clearly don't need that, so I can reduce it. That's going to reduce the number of calories that you need for your muscles. So actually you can use this for something else because you know getting calories is hard as far as our body is concerned. Even though it's no longer true, we can get them really easily at the
convenience store.

[00:29:58] Daniel Lieberman: Correct, and so the hunter gatherers that I've met but i haven't met that many because there aren't that many on the planet. But you know also if you look at the literature, you know they're reasonably fit and strong but they're not, none of them are bulked up, they're not super strong, right? 
Because they mostly engage in endurance, not that much strength and physical activity. So that's one myth. 

Another myth is that they never sit. And a former student of mine, Dave Reichlen, who's at the University of Southern California did a wonderful paper a few years ago in the proceedings of National Academy of Science showing that actually, if you look at, sitting time, they're not, of course, in chairs like the ones we're sitting in right now. They actually sit as much as Westerners, right? 

Because you know, if you're not being physically active, like, well, it makes sense to save energy, right? And you know, my dog sits, cows sit, you know, birds sit, I mean, moose sit, every animal sits. 
Why shouldn't humans sit? 

So this idea that sitting is the new smoking is, I think, has been exaggerated. The average Hadza, for example, these are hunter gatherers in Tanzania that have been well studied. I mean, they're putting sensors on them. They sit 9.9 hours a day. 

[00:31:11] Jonathan Wolf: Wow, because I feel like that's what everybody's been told now, post-pandemic, you know, on their Zoom, that they mustn't do, is sort of sit 8 hours a day. But you're saying that the Hadza do it quite, the Hadza do more sitting. 


[00:31:23] Daniel Lieberman: Yes. Now, of course, the thing is that when they're not sitting, they're being physically active. So the problem is, if you look at the epidemiological data on sitting, it turns out that it's not work time sitting that's so associated with bad health. It's actually leisure time sitting. 

So if you spend all your day sitting at work and then you go home and you sit all evening watching television and you sit in your car getting to work and you sit in your car getting, you know, if you never are physically active then of course you're going to pay a price for that.


[00:31:49] Jonathan Wolf: But it's not the sitting itself which is bad, it's the fact that you're not doing any of this activity on top. Which because our normal experience, you're saying, as human beings, is quite a lot of sitting. But then quite a lot of physical activity to live and our issue is, we've kept the sitting, but we've also got rid of the rest of this physical activity and turned that into more sitting. 


[00:32:11] Daniel Lieberman: That's part of it. And the other is how long you sit, what's called the sitting bout. So it turns out that if you spend time in a hunter gatherer camp or in a village of farmers or whatever, and, you know, people are sitting, but then they're getting up constantly. They're getting up because of the kids, they're getting up to cook, they're getting up to do this, they're getting up... 
So, the average amount of time they spend sitting at any one moment, at any one bout, is about 15 minutes. 


[00:32:33] Jonathan Wolf: Okay, so they're like sitting for three hours at a stretch, absorbed in their...  


[00:32:39] Daniel Lieberman: Watching the telly, right, exactly. So, and it turns out that... Intermittent sitting or interrupted sitting turns out to be much healthier than uninterrupted sitting. Because when you get up, you're actually turning on your muscles. You're turning on all kinds of machinery in your body that it's almost like turning the engine in your car on right? 


[00:32:55] Jonathan Wolf: Interesting. So even when we go back to the sitting, then there is a takeaway here is it, which is that… 

[00:32:57] Daniel Lieberman: get up every once in a while.

[00:33:00] Jonathan Wolf: You might be alright if you're constantly getting up, but sitting for a prolonged period of time is not good for us, and it's not how we're naturally evolved to be. 


[00:33:10] Daniel Lieberman: Right, so some people have phones that tell them, you know, or their wristwatch buzzes every 15 minutes and tells them to get up and go pee or make a cup of tea or whatever. That's all good.  


[00:33:18] Jonathan Wolf: Hi, I hope you've enjoyed our journey back in time today, getting exercise advice informed by the way our ancestors lived. 


Talking about going back in time, we've actually had 18 months of conversations like this with world leading scientists, all focused on getting you to a longer, healthier life. Now if you're short on time and want the key takeaways, without all those hours of listening, we've got you covered. Our team has just created a free guide summarizing the top 10 discoveries from our podcast that can make a real difference in your life. 


To get it, simply go to zoe.com/free guide or click the link in the show notes and please let me know what you think of it. Okay, back to the show. 

One of the things I like about this is I get teased a lot by my wife because I like to drink tea quite a lot and so that means that, and I get teased a bit at work as well. It means sort of after every meeting basically I'm like oh well I need to go make a cup of tea and obviously that means I can't sit at my desk, I have to go make the cup of tea and come back. And of course if you drink lots more fluid, then you need to go to the toilet more often as well. 

So now I can say well it's really important for my health because a world leading professor has explained this makes me more like the way I was supposed to be. Is that right?  


[00:34:34] Daniel Lieberman: Yes. Not only because it makes you more like you're supposed to be, it's just there's, even without knowing that hunter gatherers did it, it turns out to be healthy. 

[00:34:43] Jonathan Wolf: Do we need to make fundamental changes to the way that somehow our lives are ordered in order to start to move? Because our lives are very different, right? And so clearly we're not going to end up living a life in the way that our ancestors did. You're not suggesting that we get rid of the water in our house and things like this, presumably. 

So, do you need to make lots of very intentional decisions in order to try and get closer to sort of the way that we need to live in order to be healthy? 


[00:35:13] Daniel Lieberman: I think the answer is kind of obviously yes. You know, we live in a world where our life is mismatched to our biology in many ways, right? 

Think about the diseases that are more common today, type 2 diabetes, heart disease, cancers, arthritis, osteoporosis, depression, anxiety. All of these are much more common today than they were in the past. 
And we have good data to show that, right? 

And by the past, I don't mean actually even that long ago. And most of those diseases, you know, most of the time when somebody walks into a doctor's office for a health visit, the vast majority of those visits are for preventable diseases, the vast majority, at least 70 percent by, by most estimates. 


And how do you prevent those diseases? Well, I mean, over and over and over and over, it comes down to a few just simple basic things. Apart from not smoking, right? It's diet and exercise. Sleep is also important, of course. You know, avoiding psychosocial stress is important. But diet and exercise are obviously fundamental. 
And we live in a world, however, where we no longer have to be physically active, so we have to exercise.

[00:36:19] Jonathan Wolf:  And tell me a bit more about it, because I think it is an interesting point that you're making is that we didn't exercise before, we just had a life where you got sort of this activity. 

So what are, you know, is there such a thing as a typical hunter gatherer lifestyle. Is it very clear the sort of activities they did that therefore we need to build, or is that actually, help us to understand. Because you mentioned already that, you know, this thing about like, we used to, we carry more, can you draw me a bit more of a picture of what is this life?


[00:36:52] Daniel Lieberman: People want a prescription, right? And that's part of the problem, which is that there is no simple prescription. 

But people were physically active. They sat, but they didn't sit for long periods of time all the time. They didn't have access to, you know, industrially processed foods that had all kinds of, you know, crap added and the fiber removed, et cetera. 


And, you know, time after time, if you look at the literature, you know, even if you didn't know anything about our hunter gatherer or farmer ancestors, you'd already know that, right? I mean, who doesn't know that exercise is good for them and not eating, you know, McDonald's every day is good for them. 
Everybody knows that. 

The problem is that we live in a world where, again, now physical activity has become optional and it's less expensive and more easy to buy industrially processed foods that are unhealthy. And so people have to now go out of, I mean, I pay more money for food that has less sugar added. 
Right.  And I have paid more money for foods in which they haven't removed the fiber for it. Right. The world has become essentially kind of topsy-turvy. So it does require us to be intentional about how we organize our lives in terms of both physical activity and diet. That's just a sad truth to our lives. 


And there are all these people out there who are trying to make money off our desire to be comfortable, off our desire to have energy rich food, you know, and we need to figure out how to overcome that. You know, everybody, I know, likes, you know, understands that exercise is good for them. 
It's just that many of us struggle in order to exercise. 

And so I think that part of the problem is that we kind of shame and blame them, right? We make them feel bad. They're somehow, they're lazy. There's something wrong with them. 

[00:38:35] Jonathan Wolf: Yeah, I think that is absolutely sort of the story that we're used to. 


It's like, we should do this and if you're not doing it, it's somehow, there's something wrong with you. Like whether it's a moral failing or a physical failing. And I feel that actually, that's got even more so in the culture over the last even like 10 years. 

[00:38:52] Daniel Lieberman:  Absolutely. The physical activity culture is such that, you know, just go do it, right? 
You know, just do it, and all those other, you know. 

We need to understand that if you look, if you put couches and, and escalators and you know, nice comfy chairs and whatever in the Kalahari desert, the hunter gatherers there would avail themselves of them just as much as you and I do. 
Right. 

So we need to find ways to help people help themselves without being dictatorial, you know, not being sort of, you know, fascistic about it. And that means finding ways to help people either make physical activity necessary, or make it rewarding, or both. And that's, I think, our societal challenge. 


[00:39:36] Jonathan Wolf:  And I'd love to talk about that. Just before we do, there were a couple of these myths that I would, I would love just to cover first. 

So one I think you mentioned at the beginning, the quickfire questions about this idea that when you get old you should retire and slow down. Is that true?

[00:39:52] Daniel Lieberman:  Very much no. 
So, we actually published a paper recently called the Active Grandparent Hypothesis. 

So you may have heard of the Grandparent Hypothesis, the idea that humans evolved to be grandparents. Most species, very rarely do individuals live after they've stopped reproducing. Whereas the average human lives about two decades after the end of reproduction, which makes us very unusual by the species. 


And one of the reasons, of course, is that old people impart wisdom. We talked about that earlier. But also, if you go to any non-, you know, pre-industrial society, The grandparents are out there in the fields digging and farming. The grandparents are out in the hunter gatherers out there, you know, digging for food and hunting and providing food for their children and grandchildren. 


We evolved to stay active all throughout our lives. And what's important about that is that being active slows the aging process. We can talk about why that is the case. And promotes health, both mental and physical, which thereby enables people to actually live longer. So it's a feedback system. 


Because remember, until recently, we make a distinction between health span and life span. And until recently, there was no medical system, right, the doctors didn't exist. Your lifespan was your healthspan, right? As soon as you got really sick, you died, right? 

What physical activity does really, it's not so much important for lengthening lifespan, although it does. What's really important is extends your healthspan by slowing aging and turning on repair and maintenance mechanisms that keep your body functioning really well. 


And so the fact that people evolved to be physically active as they aged, actually helped them age so that they could be actor grandparents.  


[00:41:37] Jonathan Wolf: And I feel a lot of people listening to this are like... slightly blown their mind because I think we are absolutely used to this idea that there's this big distinction between a grandparent and a parent. And grandparents definitely are not like going out, you know, in the equivalent of the hunting and digging in the field. 


It's like, well you know, obviously they'll be too frail, they won't be strong enough. That's a different thing. And now, if I was thinking back to this hunter gatherer, it'd be like, well, I assume that they sort of sit in the middle of the village and look after the little children so that, you know, the people in their 20s and 30s can go out and do these really physical things. 



[00:42:14] Daniel Lieberman: Nothing could be further from the truth. So there's a wonderful study by an anthropologist named Kristen Hawkes, who showed that among the Hadza, again, we'll always go back to the Hadza, because they're pretty much the best study of the hunter gatherer group. The grandmothers actually spend more time digging up tubers, you know, food, than the mothers. 


[00:42:32] Jonathan Wolf: Grandmothers do more digging than the mothers.  


[00:42:33] Daniel Lieberman: Yes, because, because mothers are dealing with their children, right? You know, there's a handful, right? Grandma can go off and spend more time, of course, they also do a lot of childcare and other things like that. They can actually spend more time. They end up digging more tubers. 
I've seen this myself. 

Some of these Grandmas, like, my God, they're like machines. They're like, it's hard to keep up with them. They're like digging machines, right? So they're actually working harder than the mothers. And of course they're not doing it as a form of exercise. They're doing it to help their children and their children and their grandchildren. 


But here's the thing. It actually helps them. There was a, the most famous study on exercise and aging was actually done here in Boston at Harvard Medical School by a guy named Ralph Paffenbarger. He figured out that if you wanted to study aging and exercise, Harvard was actually like the best place on the planet. 


And the reason for that is that the Harvard Alumni Association, the development office, never lets go of its alums because they're constantly asking them for money. You never, never get left alone. Until the day you die. Harvard will ask you for money. 

And because of that, he thought. This is perfect. We can get the Harvard alumna, you know, the development office to let us follow a bunch of Harvard alums as they age, find out how they're doing, give them some questionnaire, you know, find out how active they are, whether they smoke and what, et cetera, and then find out effects on aging. 


And what he showed was, and of course it's been replicated many times, but this is a classic paper in the New England Journal of Medicine, showed that as people get older, the effective exercise increases their lifespan more. 

So, for example, Harvard alums who were in the, you know, 20 or 30 or 40 years old who exercised more than the sedentary alums from the same class, they had about a 20 percent lower death rate. 
By the time in their 60s or 70s or 80s, after correcting for other factors, they had a 50 percent lower death rate. 


[00:44:26] Jonathan Wolf: So, once you're in your 60s, 70s, 80s, the people exercising were having a 50 percent lower death rate than the others.

[00:44:33] Daniel Lieberman:  In other words, the other way of saying it is that the older you get, the bigger the benefit of exercise is on your longevity. 


And since then, we understand the mechanisms behind that. Because every time you exercise or for that matter, are physically active, climb the stairs, or, you know, go dig up some tubers, or carry water instead of turning on the fire, whatever it is you do, right? 

What, what you're doing is you're stressing your body, right? 
The muscles are, you know, getting little tears. The mitochondria in your muscles, those are little organelles that produce energy, they're actually producing reactive oxygen species. They're actually causing oxidation, like, you know, when you brown an apple, right, they're producing these little chemicals that are reactive, right? 
You're heating up. And so you're actually, you know, changing, you're damaging your proteins. There's a thousand bad things that happen. Okay. 

[00:45:23] Jonathan Wolf: So this sounds bad. You're describing all the bad things. 

[00:45:26] Daniel Lieberman: It's stressful. It's a physiological stress in every single system of your body stress. However, we evolved to be physically active, right? 

So for every single one of these stresses, our bodies turn on repair and maintenance mechanisms. So we turn on, we produce antioxidants that mop up all those free radicals,  those reactive oxygen species. We produce proteins and enzymes that get rid of the proteins that have been damaged. We produce enzymes that repair the mutations that are caused in our DNA by the exercise. I mean, I could go on, right? 

Every single thing you can think about, right, has been natural selection over billions of generations of not just humans, but our ancestors, has produced responses so that it, that physical activity isn't damaging for us. It's actually the reverse. 

[00:46:09] Jonathan Wolf: But you need to do the physical activity in order to trigger all of these beneficial effects.   


[00:46:14] Daniel Lieberman: Exactly. Because we never evolved not to be physically active. So we never evolved to turn on these mechanisms in the absence of physical activity.  


[00:46:20] Jonathan Wolf: You're saying we're evolved and our bodies are like, well, obviously I'll only turn on the repair after the damage and it never imagined that you might be able to go through a whole day without having to do lots of activity and set it off.

[00:46:30] Daniel Lieberman: That's part of it. And the other is that, of course, you wouldn't want to, it's very hard to program the body just to repair exactly that damage. Right. You tend to overshoot. Right. 

So the analogy I often use is like imagining you spilled your tea on the floor right now and you then cleaned it up. The floor would actually be a little bit cleaner after you cleaned it up, right? Because then, than it is right now, cause it's actually not all that clean. Right? 

So, and that's exactly the same with these repair and maintenance mechanisms. We actually tend to overshoot them. And so the end result is that physical activity isn't bad for us otherwise people who exercise would die younger, right? Instead, we turn on these repair and maintenance mechanisms that actually prevent that actually…

[00:47:10] Jonathan Wolf: That actually improve every aspect of ourselves. 

[00:47:10] Daniel Lieberman: We overdo it, which is why exercise slows aging because you actually slow, through these repair and maintenance mechanisms, the aging process. 


[00:47:17] Jonathan Wolf:  And we don't, we haven't invented a way to pop a pill that just switches on these repair mechanisms. 

[00:47:23] Daniel Lieberman: And we never will because you’d have to take an entire pharmacy every day. 
And furthermore, every single one of those pills would have side effects. 

There's one other important benefit of exercise when you're younger, which is that exercise. Remember we talked earlier about energy, right? And there's only so much energy you have. Well, it turns out that if you're physically inactive, if I don't exercise, my body will think, Oh, hey, extra energy. 
Let's turn up the hormones. 

And this is especially true in women. So women who are inactive have higher levels of estrogen and progesterone. And of course, that's the body's natural way to try to increase fertility. But there's actually, there are already plenty fertile, right? So what happens is that you're actually unnaturally turning up reproductive hormones, which increases the risk of cancer. 


So people who are physically active actually have lower risks of cancer. Breast cancer rates are between 30 and 50 percent lower. I'll say that again. Between 30 and 50 percent lower in people who just get 150 minutes a week of exercise. That's 20 minutes a day. 

[00:48:25] Jonathan Wolf: That's amazing. 

[00:48:26] Daniel Lieberman: And the reason for that is partly because of this energy. 

I'll give you another example. Remember, we talked about repair and maintenance mechanisms. When you go out there and do stuff, right, you're encountering the outside world, you turn on your immune system. 

One of the cell types that gets turned on by exercise are cells called natural killer cells, which sound awful, but they're also called cytotoxic T cells, again sound a little scary. But these are the cells that protect us against cancer. They also protect us against viral infections and various other things. We heard about them a lot during COVID. 

So people who exercise actually are turning on the cell types and then moving them about their body through the circulatory system, thereby protecting them from the damage that they might get, but also from damage that comes from cancer. Natural killer cells are our first line of defense against cancerous cells. 

So if you look at the data, almost every single form of cancer, with almost no exceptions, people have significantly lower rates of cancer if they're regularly physically active. And that's again because of we turn on these systems that we don't otherwise turn on in the absence of physical activity. 


[00:49:42] Jonathan Wolf: It's amazing. So that's an incredibly strong argument you're putting forward about physical activity and exercise. And I'd love therefore to start to talk about practical advice because you also started the beginning by saying we're all naturally set up to try and avoid doing any unnecessary activities. 


So there's this huge tension between all this amazing impact on our health and actually how we're naturally evolved to avoid doing any of this. 

So I would love some really smart insight. You know, most people listening to this are therefore going to be saying, I sort of hate exercise. I'm hearing you say that it's important, but, you know, people tell me about important things I should do all the time, but, you know, it's still hard to do. 
Is there any insight from everything that you've learned that can help us to understand how we can try and find a way to do this activity?  


[00:50:43] Daniel Lieberman: Well, again, I, you know, I'm not a psychologist, so you should take my advice with a grain of salt. But again, I go back to this first principle, which is that we evolve to be physically active for two reasons, and two reasons only, when it's necessary or rewarding. 


And the fact of the matter is, we're not going to make it necessary for most people, right? Most people don't have to be physically active in order to survive. So I think we should focus more on the rewarding bit. And for me, the most rewarding kinds of physical activity, and I think it's true for most people, is making it social. 


I mean, just think about the way a lot of people, like, when they complain to me about exercise, they, you know, I go to the gym and I go on the treadmill and I hate it. You know, maybe they'll make it rewarding by listening to this podcast or something like that. You know, sometimes when I. I'm forced inside on a treadmill. 
I mean, believe me, I'm not, you know, I listen to something or watch something or whatever. 

But really the best social activities are when you're with a friend, right? When you're with other people and you, it ceases to be exercise, it becomes fun, right?  


[00:51:44] Jonathan Wolf:  Is that why sport is sort of sport rather than exercise, because actually it's social, and it's got this sort of competitive element. 

[00:51:55] Daniel Lieberman: Yeah, if you're tired, your friends say, Hey, come on, keep going and whatever. And you have like a little peer pressure to keep going. And you know, the miles pass by if you're running or whatever it is you're doing. Or going for a walk or whatever you go for a walk with a friend that you don't think of it as exercise. You're going for a walk with a friend. Right. 

And so I think. We, you know, dancing, you mentioned it earlier, dancing is exercise, right? But, but we don't think of it as that. We think of it as a social activity. And why not have, why don't we, why don't we have more public dancing? Why don't we have more, you know, towns and cities have, you know, bands on street corners for people to go dancing in the evening? 
I mean, we can think of all kinds of ways of doing this, right? And, but we don't, because I think our imaginations have been limited by the way we've industrialized and corporatized physical activity, and it doesn't have to be any of those things. 

There's nothing wrong with, with, you know, with it, but it doesn't, it doesn't really work. 


[00:52:45] Jonathan Wolf: What is the sorts of exercises you think that we need to do because again, I think this is also an area where there's a lot of myths, right? About you know, you must do 10,000 steps or you need to do, you know, these particular sorts of exercises. What is…

[00:53:02] Daniel Lieberman: Well, that's part of the medicalization of exercise, right? 


We prescribe it like a pill right and you know, it doesn't work that way, right? It depends on who you, are how old you are, what your issues are. Are you worried about Alzheimer's? Are you worried about cancer, are you worried about heart disease, etc. Are you injured? Are you unfit? 
Are you overweight? 

There's never going to be one solution, but I would say this, and I think there's some very, some simple principles, which is that no matter who you are, some is better than none, right? Just a few thousand steps a day has been shown, and that's not a lot, that much, a few thousand steps a day has been shown to provide benefits over none. 


And furthermore, the more you do, you get increasing benefits, but those benefits tend to tail off, right? So you don't need to run marathons or ultramarathons. In fact, it's not going to help you at all. 

And we didn't evolve to do any one thing, right? We didn't evolve just to walk, although walking is the most fundamental form of physical activity.
We also evolved to, you know, carry things and pick things up and whatever. And so mixing it up is always a good, good idea. 

[00:54:04] Jonathan Wolf: So would just walking be sufficient activity for people or are you saying actually, it's better than nothing, but there's clearly other things you need to do to sort of, which is a bit what I've taken away.


[00:54:15] Daniel Lieberman: I don't really  know what sufficient means, right? And again, whatever you do is better than none. So if all that you can do is get some walking in, that's fine. But if you have the ability or the inclination to do more than walking and do a little vigorous physical activity, because walking is what we call moderate physical activity, right? 


You get your heart rate up to about 50 percent of your maximum for walking, which is good, right? Walking is the most fundamental, basic form of physical activity, bar none. So if you're going to do anything, walk. 

[00:54:43] Jonathan Wolf: And this
is back to your saying that it's amazing how far people walk in these hunter gatherer environments. And I think you mentioned also that they're not. necessarily sort of running as much as maybe we had this…  


[00:54:54] Daniel Lieberman: Well, they run sometimes, but you know, they don't like running every day. They're not running five miles every morning, right? Maybe once a week they might do some running, you know.  


[00:55:02] Jonathan Wolf: So you're saying it's not like every day they are running in order to do something they have to do. 


[00:55:06] Daniel Lieberman: No. Definitely not. 

[00:55:08] Jonathan Wolf: I love the way you say some of these things is that they're so obvious from your experience. It's really fun. And I'm like, I have absolutely no idea, in fact, what would be normal in this environment. 

[00:55:14] Daniel Lieberman: But again, it's just because it's normal doesn't mean that's what we should do. That's, that's the myth of the paleo diet, right? 


If you, if you eat like hunter gatherer ancestors, you're going to be, you know, it doesn't work that way, right? Our ancestors didn't evolve to be physically active in order to be healthy. They evolved to be physically active in order to survive and reproduce. 

So it's not a blueprint for exactly how we should be today. It just gives us information about what we evolved to do, and that helps us understand the mismatches that we have in the world today. But it's not a prescription. 

[00:55:42] Jonathan Wolf: Okay, it doesn't mean we have to live exactly the life, because I think a lot of people are listening to this and saying, so we should be trying to live as close as possible to that. 


[00:55:48] Daniel Lieberman: That's facile, that’s wrong. That's a very bad way of using evolutionary data. And that's the myth of the paleo diet.  


[00:55:54] Jonathan Wolf: You're saying it's facile but I think it's not meaning like it's obviously not true. 


[00:55:58] Daniel Lieberman: Also, they didn't have medicine. They didn't have refrigerators. They didn't have, you know, there's all kinds of good things we've invented today. 


And that, should we abandon those because the hunter gatherers didn't have that? 


[00:56:06] Jonathan Wolf: So it's sort of trying to understand which of those things, by not having are hurting us and adjusting for that, rather than just assuming that everything they did like just assuming their diet is better always or that they're particularly… So that's not always the right answer.  


[00:56:18] Daniel Lieberman: Yeah, we call that the naturalistic fallacy. That what was, you know, done in the past and what's natural must necessarily be better. Sometimes it is. It's a reasonable, you know, way to start thinking about things, but we use science to sort of test these ideas. 


[00:56:33] Jonathan Wolf: So this is like saying, we now know that if you boil the water, it gets rid of the germs. That's a good thing. We don't, and the fact that we didn't do that in the past doesn't mean that… 


[00:56:40] Daniel Lieberman: Yes. Hunter gathers only had unboiled water. Therefore, I'm never going to have boiled water. Okay.  


[00:56:45] Jonathan Wolf: So that's an example where you're saying, actually, we could have made, you know, there's just progress that we didn't understand. 


[00:56:50] Daniel Lieberman: Yes, we don't have to abandon, abandon all kinds of modern things.  


[00:56:52] Jonathan Wolf: And so the reason why you talk about the activity is that it's, our body is sort of requiring this activity in order to trigger all of this maintenance and repair. And we haven't come up with an alternative today in our lifestyle to solve for that. So we need to create this activity to trigger it. 


[00:57:07] Daniel Lieberman: Yes. Our bodies evolved to acquire some degree of physical activity to turn on all these repair and maintenance mechanisms, to modulate our hormone levels, all these sorts of things. And if you remove them from our environment, we run into trouble. 


So, the bottom line is get some physical activity, more is better than none, and mix it up. And if you're going to try to do it, if you're struggling to do it, A, don't feel bad about yourself. There's nothing wrong with you. And B, try to make it fun. You know, because if it's fun and it's social. 

So, example, I like to run. 
And I often run with friends. So on Tuesdays I run with so and so, and on Fridays I run with so and so, and on Sundays we have this big running group. And we often email each other the night before. It's like, hey, let's meet on Tuesday at 7.15. And I guarantee you at Tuesday at seven o'clock, it's like, Oh my God, I'm like, What am I doing? 


I don't, I know it's raining or it's cold. Or I've got like, I've got to work on this paper, I got to get ready for class or whatever, you know, whatever. And I don't want to do it. But I've already promised, you know, my friend, Aaron, that I'm going to be there. And if I'm not there, he's going to be pissed off. 


And so I go and you know, we're often like grumbling in the morning, and neither of us want to see each other. And then, you know, after 10, 15 minutes, you know it's fun. It's good. So, we've made it necessary for each other.  


[00:58:32] Jonathan Wolf: So, you've made this commitment, it's forcing you to do it, and then in the end, then it…


[00:58:35] Daniel Lieberman: And it's also social, because, you know, he's a good friend, and we have a, we chat about this, that, and the other, and, uh, so we've made it both necessary and social. 


And there's all kinds of ways to do that. You can, you know join a club, or have a gym, or, you know, there's, have a trainer, I mean, if you have money, whatever, there's a thousand ways of doing that, and we all have to find our own ways of doing it. 

But that I know works. And people who tell me that, you know, they're struggling or the other thing is that we often engage in hyperbolic discounting, which is a fancy word of saying, I'll do it next time. 


You know, it's the famous marshmallow test, right? You know, you can have one marshmallow now, but if you wait 20 minutes, you can have two marshmallows, right? And we're very bad about that, right? 

And so, how often do we, like, I walk into the building I, I, I work in, right? I'm, my office is on the fifth floor. 
It's an old Victorian building. And I can guarantee you, every single time I walk into the building, I would like to take the elevator, right? Every single time. But I don't, and I think, okay, you know what, I'll take it today, tomorrow I'll take the elevator. The only reason I don't take the elevator is that if anybody sees me on the elevator, they'll call me a hypocrite, right? 
Because I talk about it. 

[00:59:51] Jonathan Wolf: You sort of force yourself to take the stairs by declaiming how terrible it would be.  


[00:59:55] Daniel Lieberman: But every time I get there my brain does this little hyperbolic discounting trick saying, you know what, maybe you can get away with it. Tomorrow, tomorrow I'll take the stairs, right? I'm no different from anybody else. 


So we need ways to trick ourselves out of that kind of hyperbolic discounting, because it's a natural, basic, fundamental instinct. We all do it. I don't care who you are. 


[01:00:17] Jonathan Wolf: Now you've talked quite a bit about walking and how that's important in doing more activity. I was interested in about the sort of weights and carrying, because you sort of touched on that a bit and I think for a lot of people, they tend to think about exercise as like it means you're going for a run.

[01:00:34] Daniel Lieberman: But weights are important too. 


[01:00:35] Jonathan Wolf: Yeah. So could you tell me about those two?

[01:00:37] Daniel Lieberman: So weights actually really important for aging, because one of the big issues for aging in the Western world is something called sarcopenia, which is a long, fancy word, which means just basically you're getting frail. So sarco- means muscle, and -penia means loss, so muscle loss. 


And as people get older they tend to lose muscle mass. And they get frail and, you know, getting out of a chair is difficult and, you know, doing basic tasks is difficult. And when that happens, you become less physically active. And then that further exacerbates the muscle loss, right? So it's a vicious circle. 


And then, of course, it becomes very serious because then you have loss of quality of life. And then you're less able to walk, your walking slows down. All of these things happen. 

The way to prevent sarcopenia is to do some strength training. Right, again, because I don't... I live in a world, I don't have to carry water. I don't have to carry anything in my life. So I do, like you, I go to the gym and I have weights and I lift them and I hate doing them. But as we get older… 


[01:01:37] Jonathan Wolf: But you feel that is an essential thing that you need to do.  


[01:01:39] Daniel Lieberman: It's absolutely important. So pretty much every major health organization recommends that as people get older, it's critical that they do weight training at least twice a week. 
And you don't have to do crazy amounts of weight, just enough to kind of…


[01:01:51] Jonathan Wolf: And it and it sounds like you're saying that, you know, in these tribes that you visit, all these grandparents are just carrying lots of heavy weights all the time.  


[01:01:58] Daniel Lieberman: No, but they're carrying food. They're, I mean, they're not carrying weights.


[01:02:00] Jonathan Wolf: But not weights, but I mean, like things that are heavy, they are just carrying things. 

[01:02:05] Daniel Lieberman: Yes, there are,  there are no, there's no shopping carts. There are no cars.


[01:02:08] Jonathan Wolf:  But their children aren't doing this for them.  


[01:02:09] Daniel Lieberman: They have to carry their children, right? Yeah, at a certain point, the children can help carry them, but there's always babies to carry. 
And there's, you know, when you go out and dig a bunch of tubers, you got to bring them home, right? There's not gonna, you can't call an Uber and have the Uber deliver it.  


[01:02:21] Jonathan Wolf:  I think what's really interesting is I'm, I've still got, you know, I've still got this thing in my mind about, well, okay, but if, if they're you know, in their 40s or 50s, they have grown up children, aren't their grown up children doing all of this for them so they don't need to carry these things? 


[01:02:36] Daniel Lieberman: Not in the slightest, no. Everybody works, everybody carries. You go out and hunt, you know, a kudu, you know, you can't just let it sit there, right? You have to bring the kudu home, right? 

[01:02:46] Jonathan Wolf: And so 
everybody's just still strong.  


[01:02:48] Daniel Lieberman: Because they have to use their bodies, you know, and they're not doing crazy stuff, right? So you don't need to, and so the studies show that, you know, just a moderate level of, you know, 10 to 12 repetitions, several of those, you know, in various basic muscle groups, doesn't have to be really super heavy weights is enough to basically prevent that kind of muscle loss. 


[01:03:11] Jonathan Wolf: And that's like twice a week, not crazy, is already this transformation.  


[01:03:14] Daniel Lieberman: I mean, and also you can build in, like I have this, one of the ways I do it is that every morning I make coffee for my wife and myself. We have a french press and I leave the coffee. in the French press for four minutes. 
And while that's doing, I go to the living room and I do push ups. I hate the push ups. I promise you, I do not enjoy doing that, but I've made that my little habit. And now I know that when the coffee's there, I have to do my little push ups and it works. And it's one of the ways I sort of trick myself into doing…

[01:03:42] Jonathan Wolf: Because at least you get coffee at the end.Is that what you're saying?  


[01:03:43] Daniel Lieberman: I get coffee at the end and it's just like my habit.   


[01:03:46] Jonathan Wolf: I’m impressed. You're quite disciplined there because I think unless I had a trainer or somebody leaning over me, which is my hack on this is like, I need someone to make me do it. 


[01:03:55] Daniel Lieberman: But I've made it a habit. Habits are useful, so it's now a habit and trust me, I don't ever really want to do it, but I got to grumble and whatever. And also, I also know that if I'm going to, you know, talk to somebody like you, I don't want to, you know, be a liar. 


[01:04:09] Jonathan Wolf: Could you tell me, is there any difference in this advice between men and women?

[01:04:13] Daniel Lieberman: No. Absolutely not. I mean, both men and women evolved to be physically active. And it's important for both it's important for everyone and I would say these are universal.

[01:04:30] Jonathan Wolf:  So I'd love to almost wrap that up just by, you helping me to sort of summarize your weekly exercise routine, because I think we got bits of that through the podcast. But I think it would be interesting to see how that is. 


[01:04:42] Daniel Lieberman: I'm a little weird. 

[01:04:44] Jonathan Wolf: How that is. Well tell us. I think lots of people are gonna be interested. It's like, okay, you say all of this, but what do you really do, Daniel?  


[01:04:50] Daniel Lieberman: Well, I love to run. Okay.


[01:04:51] Jonathan Wolf: So you genuinely take pleasure from this? Despite everything you've said up till now, actually, you enjoy it. 


[01:04:56] Daniel Lieberman: Well, I genuinely take pleasure from running, but I never really enjoy the first few miles of any run, or very rarely, right? But I like to run, and so I usually run, you know, 5 times a week.

Sometimes I do spin cycling, cycle in the basement. And I try to do weights, you know, just a, just a few, not a huge amount, about twice a week. You know, I do squats and things like that. I do my push ups when I make my coffee. 

I try to get up every once in a while and, like you, I'm a tea drinker and so I'm getting up to make my tea and then microwave my tea because it gets cold and, you know, all that sort of stuff. And that's about it. 


[01:05:35] Jonathan Wolf: It's quite impressive. Like, that's a high level of activity, and what fraction of that, like if somebody told you tomorrow, we have got this magic pill, so, you know, we can sort out the health bit. What would you still be doing? 


[01:05:49] Daniel Lieberman: I wouldn't believe you because there is, first of all, exercise itself is no magic pill. I mean, sometimes it's oversold as being, you know, and I hope I haven't oversold it. I mean, it reduces your risk of cancer, but it's not going to prevent you necessarily from getting cancer. But again, I participate in, I do exercise not only because it makes me feel good and makes me feel vital and vigorous and healthy, but also it's the way I've made a lot of friends. 
I mean, some of my best friends are my running partners, right? It's a part of my life.  


[01:06:20] Jonathan Wolf: So this is like back to talking about the dancing. Once it becomes just fun and pleasurable, then it's not just being done for health and therefore it's easier to stick with than something that you might not.

[01:06:29] Daniel Lieberman: So I don't think of running as just exercise. 
Running is part of my social life. Yeah, I run sometimes in the morning by myself, but I often run with friends. So it's, you know, I would say a large percentage of my friends are, I met or made friends through, through running.  


[01:06:44] Jonathan Wolf: Amazing. I have so many more questions, but unfortunately we're at time. 

So I think we started talking about like exercise, and this idea that our ancestors used to exercise is just wrong. What they used to do is a lot of physical activity, largely because they had no choice. If you wanted to get water or food or any of it, you have to do this. 

And that because, until very recently, we were always in this desperate need to try and find enough calories just to sustain us and have children and all the rest of it. We've sort of evolved to minimize the waste. So why would you do a whole bunch of exercise if you don't need to? 

And similarly you know, our muscles are designed to shrink if they're not actively used because they have this cost of calories to support them. So there were no like massive Tarzans, you know, walking around everywhere unless they really really needed it. 


And so unfortunately we're in this world where our muscles naturally want to shrink and we're not anymore doing any of this activity so that's very different. 

And I think you also talked about the way in which we now understand that although this activity in the short term can create damage to our body in lots of ways, it switches on these amazing repair mechanisms and the total impact of that is actually, it's repairing all of us. 


So if we are being active, we're actually repairing our bodies, and if we stop being active, suddenly these, these systems that should be working all the time just aren't. And therefore you describe these amazing statistics, I think, about how, you know, in your 60s, 70s, 80s, if you're being active, then, you know, your chance of dying each year I think was like 50 percent lower. 
So this is a huge change. 

You also said that it's a complete illusion that as we get older, we should stop doing exercise. And so this thing that I think we are all used to in the West is not at all the patterns that you've seen visiting all of these different hunter gatherer tribes where, you know, you might be a grandmother or grandfather. 
You keep digging the tubers and carrying the water and everything else and as a result you're much, much stronger than we would be here today and that loss of strength is a huge risk factor for all of us. And unfortunately that means you need to carry some weight.

So I think in terms of then talking about actionable advice, we do need to do activity, we need to do walking, but you also need to do weights. And we need to fight sort of this natural desire not to do it. 

And I think you gave us some really great tips of which I think the thing you were most interested in is like, make it social. So suddenly this thing is, if this can be fun, it's no longer just this really tiresome thing of, you know, going off to the gym on your own, but actually you're going to meet friends or you're going dancing or, you know, whatever those things are, then it makes it much easier because it's natural not to want to do exercise.

And this idea that if anyone's listening to this that, you know, there's something wrong with them. They don't want to do it. You're actually saying it's the reverse. Of course you don't want to do it. You need to create ways to want to do this activity. And the good news though is if you, if you do it, then it really affects your health. 


And I think the other thing you'd sort of talked a bit about is sometimes the start of it is what's worse. So you're saying, I actually, you hate starting running, but then actually you quite enjoy it later. So there is a sort of positivity at the end of this, if you can get over this, this initial hump. 

[01:10:06] Daniel Lieberman: I would say that's an A. 


[01:10:08] Jonathan Wolf: Thank you very much. I thought this was so interesting. I hope I can tempt you back in the future because I know there's a lot of things we didn't talk about like sleep and various other areas. .  


[01:10:20] Daniel Lieberman: It would be a pleasure.

[01:10:21] Jonathan Wolf: Thank you. 

[01:10:22] Daniel Lieberman: Thank you.  


[01:10:24] Jonathan Wolf: Thank you, Daniel, for joining me on ZOE Science & Nutrition today. 


We've shattered some myths, made me feel a lot better that I don't enjoy exercise, and also heard some practical tips on how we can reap its benefits. But to really optimize our health, we must also ensure that our bodies receive the right nutrition. And if you want to understand how to support your body with the best foods for you, then you may want to try ZOE's personalized nutrition program. 


You can learn more and get 10% off by going to zoe.com/podcast. As always, I'm your host, Jonathan Wolf. ZOE Science & Nutrition is produced by Yella Hewings-Martin, Richard Willan, and Tilly Fulford. See you next time.