Moment 206: Harvard Professor Reveals The Biggest Lies About Exercise & Weight Loss!

0:00In the first chapter of your book you say that you went to visit the Native American tribe and I'm gonna try and pronounces the Tara Humor Tara Humara and their famous for their long Running yes, what did you learn about running from them? Well, it's you know they have been famous for well over a hundred years. I mean many People have gone to study the Tara Mara and have commented on their amazing ability to run But what I really learned from them is that For them physical activity is spiritual You know, there's this book born to run that that describes their their running and calls them a hidden tribe of super athletes.

0:38They're not hidden and they're not super athletes and And the one thing that the book missed was that the main impetus for the for the running they do these famous long distance races is that it's a form of prayer It's really very beautiful and and it's it's a metaphor for for life and and and It's also an opportunity to bet in sports and all that. It's all wrapped into one and and what I've learned was that this actually used to be Almost universal among Native American populations, right? Native American tribes Everybody had long distance races and ball games and and they were all had a spiritual element.

1:19It's just that They've they've retained their traditions because they're in a very remote part of Mexico That's essentially inaccessible. We all used to do this all Humans used to do this and in fact if you think if you look around the world every population has a tradition of endurance to its events Some of the subject that you talk about you book but also outside of your book is is how We used to run um in terms of you know, I was at the foot doctor What's it called? I don't know what they're called for the podiatrist. That's what I said podiatrist I But I went to the podiatrist the other day because I I got this What's it called when you're in a point here on my foot this part of my foot here started to get lots of pain I return to the shaders that's it plan to her for shiitis.

2:08I started to get some plan to her for shiitis and it was just this ongoing pain and They prescribed me some insoles. I was done on the couple of machines some soft stuff and they measured my foot and took this scan of it and said Right, basically you're standing wrong um your arch is a bit too flat take these insoles and wear them in all of your shoes I just I always think in these moments when someone prescribes me something that's not natural. I go Why like Where did I go wrong? And I think that's the key question where did I go wrong who lied to me? To the point now that at 30 years old to have these bloody insoles that have to put in all my shoes Because presumably that's not natural presumably my my ancestors don't have bloody insoles.

2:53Yeah So Plenty of shiitis is what I would call a mismatched disease right disease that's more common or more severe because our bodies are inadequately adapted to modern environments and in your case and as as is the case with a lot of people You have a weak foot. So so we you know you look like you go to the gym. Yeah, you're a pretty fit person, right? I'll make about you you strengthen pretty much every muscles group in your body except your feet, right? I'll come in right Well, but we don't right one of the reasons is because we we encase our feet in stiff -sold shoes that are very comfortable And the reason the shoes are comfortable is that your your foot muscles have to do less work when you use using those shoes right we have shoes that are stiff souls They have arch supports right and your your foot has four layers of muscles in them And those muscles are supporting your arch And at the bottom of those four layers of muscles is this layer of connective tissue The plantar fascia and the problem with the plantar fascia is that if you stretches too much it like anything else, right?

3:53It gets inflamed But it's got almost no vascularization right so it's very hard for it to repair itself when it gets inflamed to prevent plasher plantar fasciitis The best way to preventing it is having a strong foot a strong foot to healthy foot So the way to way to treat the disease on the long term is to strengthen your foot But if you want to just alleviate the symptoms, that's what your podiatrist did by giving you an insult, right? it's basically preventing your your arch from collapsing as much making it more comfortable So your your plantar fascia gets stressed less and so it can kind of Eleviates that that that that that stretching and hence the pain right so That's a typical example of what I call dis evolution.

4:36It's what What happens when you treat the symptoms of a mismatched disease rather than their causes or preventing their causes? So podiatrist are a bit like drug pushers in that, right? Because they're they're essentially Putting your foot in the cast Right and then and for the rest of your life you kind of have to keep using them unless you strengthen your feet So I so there's nothing wrong with those you know treating the symptoms. I mean pain is no fun So where are the insults right to kind of you know, alleviate the pain But also work on strengthening your foot and I think you'll find that the plantar fasciitis will will disappear and never come back So the plantar fasciitis fasciitis has now healed After about a month of wearing the insult I no longer have the insoles with me here in New York and I don't have the many of my shoes because I've also taken a bit of time off Running on my feet.

5:28I was playing a lot of football So now I'm at a point where I can go to the preventable stage prevent it happening again And you said to strengthen my foot. How does one strengthen their foot? Good question. So there are some exercises And they're kind of foot -doming exercises and things like what you're there, you know, I can Send you some links to videos showing you some good foot strengthening exercises So that's one way to do it But the other way is to wear more minimal shoes To wear shoes that aren't stiff -sold that don't have the arch supports go barefoot a lot right And those that will naturally strengthen the muscles in your foot because you'll have to use those muscles So you've ever gone for like a long walk or run on a beach right and afterwards your your feet are kind of Tired, right?

6:08The reason your feet are tired is because you're now working on a compliant surface, right? It's not stiff. So your muscles having to work more To stiffen your foot to push you forward, right? Jack, could you go grab my the black shoe out of my bag? Showing something so So wearing shoes that aren't has stiff -sold when they don't have arch supports We'll slowly strengthen your feet, but and this is a huge butt if you do too much too fast You will your plantar fascius will come roaring back and you'll hate me You'll like you'll never forgive me because Yeah, there's a Vivo barefoot. Yeah, I wear the same shoes Oh, you've got the same shoes on Great shoes.

6:45Yeah, those are wonderful shoes those are those are the those are the exactly the kind of shoes that will help strengthen your feet These are failing a new addition in my life Yeah, they and they feel really strange because you can kind of feel the floor. Yeah, it's exactly what you've described is But but you can transition if you have a weak feet, which I'm guessing you do You if you go if you suddenly that's the only shoe you wear all the time You'll probably regret it right so so slowly slowly slowly increase the percentage of time that just like anything else If you if you like suddenly decide to lift you know huge weights that you can't lift before you'll hurt yourself right the same thing is with your feet So so slowly does it, but you if you do it gradually and slowly and carefully you can build up the strength in your foot and And you'll and you'll be a happier happier person and this is this goes back to everything else You've said about how choosing comfort choosing to have an ice supportive shoe has actually just kind of deferred a problem off into the future for me It's the same with diets the same with avoiding exercising being sedatory and and all these other things where when you choose the easy road in the short term Which is this wonderful cushion shoe I've chosen the muscle hasn't built up in my foot and I've paid the price correct So I need to again choose discomfort more in the short term go up the stairs run barefoot To avoid the late the consequences later down the line.

8:01Yeah, I mean, I know that you have to run barefoot, but Though I can be fun, but But yeah, I mean, and I can think of plenty of other examples We love comfort but comfort's not necessarily good for us There's another myth that are you bust which I thought was really interesting because I think I know a lot of people that have used this as a reason not to run they say it's really bad for your knees Oh, man, that gets me so mad, right? I mean I hear this from doctors all the time, right? Oh, yeah running is bad for your knees now. It is true That knee injuries are the most common running injuries But arthritis such as really what they're usually talking about It's absolutely definitively not true that running increases rates of knee cartilage damage in arthritis.

8:46So arthritis is caused by cartilage wearing away in a joint, right? And it's a it's a myth that that running actually increases cartilage damage If you have arthritis running is excruciating and problematic, but if you don't have it running actually If anything may be slightly preventive because cartilage joints like everything else benefits from being used, right? And so physical activity actually helps promote strong and healthy joints We used to think that it just caused them to wear away But actually, you know like cars, you know, wearing away at their tires, but now we know that actually physical activity promotes repair mechanisms and cartilage just as it does in other tissues in the body and And of course the other thing about running is that I think a lot of people run incorrectly today.

9:33So So that's why we started studying barefoot running millions, you know, along a few a bunch of a few decades ago Because if humans have been running for millions of years most of that time we were running barefoot So I'm kind of curious how did people run before shoes and what we learned was that today shoes have these cushioned heels That enabled you to essentially run the way you walk, right? You land on your heel And everybody who's barefoot sometimes lands on their heel, but people who are barefoot often More often than not land on the ball of their foot and then then let their heel down It's called a forefoot strike or a midfoot strike And when you do that we worked out the biomechanics of that and published a paper in the cover of nature showing that when you do that you actually Prevent your foot from crashing into the ground causing it what's called an impact peak a a Colligional force you run lightly and gently so if you were to take your shoes off and run up Lexington Avenue here I guarantee you you would not be landing on your heels if within a few steps you'd start landing on the ball of your foot because it hurts less And so that's how we evolved to run you we've all to run in a cushion in a way that that doesn't involve You know slamming into the ground with every step and the and that that causes less For us around your knee The trade -off though because nothing comes for free everything has trade -offs is that it's harder on your ankles Your calf muscles and your killies have to do now a lot more work to let your heel down And so people who switch from Heel striking to forefoot striking often have a killies tendon problems.

11:04They get calf muscle problems They don't do it properly. They'll get their foot muscles aren't strong enough. They'll get all kinds of foot problems Right, so you can't just suddenly become a barefoot runner and start forefoot striking If you're gonna switch you have to switch gradually and slowly and build up strength and learn to do it properly Another thing people do is they tend to run like a ballerina high up on their toes That's really hard on your ankles and your calves So you got to do it properly, but if you but it can have enormous benefits and so and we know again If you run that way there's put puts much less force on your knees and again Knees are where people get injured the most so I think a lot of knee injuries come from From the way in which we run So would you recommend if you can to run more Barefoot, especially if you have those kind of shoes we just Disgusting well, I think what matters is how you run that what's on your feet?

11:54Okay, so I would say a barefoot style How do I learn to run in a new way though? Well, I mean there's some tricks. So one of them is first of all, I don't know how you run so So maybe maybe you already run just fine But a barefoot style tends to be a high Stride right or I stride frequency so 90 strides per minute or 180 steps per minute roughly You know 170 to 180 steps per minute is about right Relatively short strides so you're not throwing your leg out and to me the most important thing is not what we call overstriding You ask any coach on the planet. They'll say overstriding is bad Overstriding is when you throw your leg out way in front of you and you land and that leg is a stiff leg So that a stiff leg means more force, right?

12:42and And it's harder on your knees And so if you and so a good runner lands With their with their shank with their tibia vertical so their ankle is below their knee when you do that Pretty much everything will work out properly, right? It'll mean that you won't land hard on your heel. It'll mean that your your leg will be acting like an excellent spring You won't produce a lot of breaking force um It's a it's a it's i to me. I think the most important skill in running is not to overstride um, and so I actually don't so don't worry about how you're gonna hit the ground Just worry about your overstride if you solve your overstride you're more likely to run well.

13:25What do you think some? What's the best kind of sort of cardiovascular exercise for the promotion of good health? Because I've been doing some cross fit stuff. I've been doing some hit workouts um I've been trying not to run because I've had a few injuries I'm trying not to run as much because it seems to be a little bit more impact And if i'm bossing myself there, but um, so I've been doing some like Hit workouts every for 30 minutes a day when I leave here Well, you do hit hit hit works every single day. Any much every day at the moment We track it with a group of friends we have there's 10 of us in a WhatsApp group Whoever's lost whoever does the least workouts every month is evicted And there's a raffle so there's a raffle yesterday on the first.

14:04Was it the first yesterday? Yeah For a new member and we do that every month and we've done it for three Half years. That's great. I've been in the first ever member. So I've been in every three and a half years Well, I think you know, I mean the most the best exercise the one you like doing But you say one that's like better, you know like the you know, I think you got to mix it up There is no one perfect exercise, right? I mean, I think what you do sounds actually pretty good, right? You're got a mixture of of You know low slow intensity Some some high intensity you want to have some strength training you want to have some cardio I mean, we never evolved to do one thing and our bodies are too complex to benefit from just one thing Mixing it up is is the obvious way to go right?

14:46I think the bedrock for any kind of physical I mean, you've asked anybody right cardio is the bedrock of of Exercise right it promotes the most health benefits right? It's good for your good, you know, you're burning energy It's good for your cardiovascular system. It's good for controlling inflammation But but but there are different kinds of cardio in high intensity versus low intensity and there's also strength training Right, which is awesome, you know important. So you know, there's no Yeah, look we tried to medicalize exercise, right? It's like a like there's a proper dose, right? You know take this pill This many milligrams this many times per week, right?

15:25Exercise It doesn't work that way. There is no there is no optimal dose Everybody's different depends on are you more worried about heart disease or Alzheimer's or Diabetes or depression or you know, are you previously injured or you Fit or you unfit there is it's impossible to prescribe exercise in this kind of medicalized way it doesn't work A lot of people exercise because they believe it will help them to lose fat Really fat the biggest debates on the planet. It has been a huge debate even on this podcast I've had multiple people come and say a whole range of things about weight loss and cardio and I'm kind of I don't know what to believe anymore Well, anybody wasn't confused doesn't understand what's going on right, you know, it's um It's sad that there's such a debate, but um, but that's how science works, right?

16:17So um As you know, I wrote about that in this book um Part of the explanation for the debate is that again What dose are you analyzing and what population in what kind of context right? So the pretty much every major health organization in the world recommends that you get 150 minutes per week of physical activity. That's kind of like the benchmark. That's what the You know the WHA WHO the World Health Organization considers the the division between being sedentary versus active So and a lot of people are unfit and overweight and struggling to be physically active I have struggled to get 150 minutes a week, right?

17:01So a lot of studies prescribed 150 minutes a week of exercise walking for example or moderate intensity Physical activity and then look at effects on weight loss and guess what when you when you walk kind of 50 minutes a week Which is what 20 minutes a day of walking? It's about a mile a mile a day You're not going to lose much weight. You're basically burning about 50 calories a day doing that right? That's a Piddling amount of calories compared to drinking a glass of orange juice, right? So So surprise surprise those kinds of studies show that Those doses of physical activity are not very effective for weight loss However plenty of rigorous controlled studies that look at higher doses of physical activity 300 minutes a week or more Find that they are effective losing for helping people lose weight But not fast and not large quantities.

17:53So you're never going to lose a lot of weight really fast by exercising It's just not going to happen because you know a cheeseburger has what you know 800 900 calories you have to run You know 15 kilometers to lose that to burn the same number of calories You're going to be hungry afterwards too. So you're going to make some of that back you have compensation So so physical activity is a is actually there's just no way around it You have to be a flat earth or not to argue this way But they're you know their physical activity can help you lose weight But it's not going to help you lose a lot of weight fast and not at the low doses that often are prescribed But the one thing that we do agree on and I think this would not be controversial is that physical activity is really important for Helping people Themselves from gaining weight or after a diet from regaining weight And there are many many studies which show this one of my favorite was a study that was done in in Boston on policemen You know policemen are kind of a reputation for you know having too many donuts and being overweight right and Boston is no exception So they did this great study at at Boston University right across across the river Where they got a bunch of policemen on a diet But Really severe diet the policemen all lost weight Some of the policemen were had to diet and exercise some just dieted alone And as you might imagine the ones who dieted plus exercise lost a little bit more weight not a lot just a little But and then they tracked them from months afterwards because most people after a diet a weight comes just crashing back The policemen who's kept exercising even after the diet was over and they went back to eating whatever the hell they wanted Donuts whatever They're the ones who kept the weight off but the ones who didn't exercise The weight came crashing back Another good example would be the have you ever seen the TV show the biggest loser?

19:36Yes, but they people going to lose weight Yeah, so that so there's crazy show right these people you know This is like totally unhealthy they were confined to a ranch in Malibu and these got these people lost ridiculous amounts of weight Guy named Kevin Hall of the National Institute of Health studied them for for years afterwards and looked at and most of them regained a lot of the weight that they lost and there was one person on the show who did not And that was the person who kept exercising And that's you know just yet more it's a one data point But there's a lot some lots of evidence to show that physical activity what it's other important benefit when it comes to weight Is is preventing weight gain or weight regain when we talk about dieting we talk about exercise or diet exercise or diet like why is it an or?

20:18I mean why isn't it exercise and diet? Diet is of course the bedrock for weight loss But exercise also plays an important role and should be part of the mix On the young police example and the biggest loser example I Can relate in the sense that when I exercise? When I go through the the moments of my life where I'm most committed to exercise I'm also most committed to my diet Yeah Because I if I go to the gym I will not then leave the gym And have a donut repeater absolutely not it seems like Wasting the effort So if you look at the sort of correlation between the moments of my life where I eat healthiest They're also the moments of my life where I'm most most focused on the gym and I noticed there was a couple of months ago Had a bit of a motivation slump managed to stay in our little WhatsApp group but Coasted down the bottom of the leaderboard for a couple of months on and just like surviving every month by one um And Through those moments my motivation in the gym had gone down and my diet had gone down the minute I managed to get in the gym into a big workout The same day my diet came back.

21:26Yeah, of course, right? They co -vary right and and that's one of the reasons why when people do big studies of Of you know what you know, you can look at what cut what what people die of right What's on the death certificate? You know cancer heart disease whenever a heart attack And then you look at what caused the cancer what caused our disease when people try to do that It's almost impossible to separate Diet and exercise because people who tend to eat better also tend to exercise more They're both in our modern upside -down chopsy -turvy world They're both markers of privilege people have money to go to the gym also have money to buy healthy foods and And people who care about their physical activity also tend to care about their diet so so At that level they're very hard to separate however if you're studying a particular component of a system In a randomized controls trial and a lab You can separate them out and so we know that they have independent and also interactive effects What is the most important thing we haven't talked about Daniel?

22:29I think the most important thing is that we need to be compassionate towards each other I mean there's so much shaming and blaming and prescriptions and You know The reason I entitled the book exercise is that people we make people feel exercised about exercise we make them feel uncomfortable and Confident and shamed and and you know here you and I are having this conversation But it can tell that you you take you know you're you're I mean I know I've listened to enough of your podcast You care about your your health and you care about diet you care about exercise and people may look at you and think Gosh I wish I was like him, but it's just not me, you know I can't I'm not I'm not there right and they may feel put off by our conversation And I think that's so often these discussions make people feel feel bad about about what they're doing And I and I and I think that what we need to emphasize is that If you put a you know if you put a chocolate cake and an apple in front of me here I would want to eat the chocolate cake and it would I might eat the apple only because you're there But if you weren't there I would eat the chocolate cake right and and when I'm in the in that in my building at and Harvard My office on the fifth floor of this old Victorian building every single day.

23:45I want to take the elevator And the only reason I take the stairs is that if anybody catches me in the elevator, I'll be a hypocrite It's not that I don't want to take the elevator. I do want to take the elevator right. I guess you guys say lift right And and and we make people feel bad for taking the elevator right They shouldn't feel bad. It's an instinct And so I think we have to figure out ways to help people Without shaming them and without blaming them and without bragging and whatever But you know, you know talking about you know the marathon they ran or this that or the other make them feel Less uncomfortable about the topic and realize that you don't have to spend the English channel or run a marathon or you know Join your What's app group and do crazy hit workouts every day by the way?

24:30You don't need to do hit workouts every day Get the benefit Instead just you know taking the stairs in your building every day Anything is better than nothing and and you'll get benefits from that and I hope that That's the message that needs to get out right anything is better than nothing And if you can get started on that on that on that pathway Then it'll eventually become self -rewarding and that and that leads me to the other topic that we didn't talk about Which is that the reward system of physical activity? You and I if we go for like I'm really looking forward to my run tomorrow morning in the park I love running central park.

25:03It's one of the best places in the world around right a fantastic view from the top and it's just gorgeous, right But when I run central park tomorrow, I'm gonna get a big dopamine hit I'm gonna my body is gonna produce all this Dopamine, which is the molecule that says to that again, right? It's a reward Gambleers get dopamine hits right People eat chocolate cake get a dopamine hit right? But if I were on fit and overweight I wouldn't get that dopamine hit and so when people start exercising They don't get the reward that people who are fit and and custom to doing it get and then they're made to feel bad Like you didn't enjoy your run around central park.

25:40Well, it takes months if not years before you actually get that reward Really? Yeah because because just like being overweight Causes you to become insensitive to insulin you become insensitive to all kinds of other hormones and neurotransmitters and dopamine is one of them So so it's not an instant like benefit, right? It's hard and so we need to be compassionate again towards people who are struggling To become fit and struggling to get the reward and also if you're overweight and you run around central park It's like if I were carrying weights and running around central park it'd be much harder right?

26:13It's you know, it's it's challenging and so we Once you get you know into that state it's hard to get back to the state of activity So we we need as a as a society to help those folks rather than judge them