The Diary Of A CEO with Steven Bartlett - Moment 209: The Real Reason You’re Gaining Weight Every Year (Even If You’re Exercising!)

Episode Date: April 18, 2025

Tried everything to lose weight and nothing’s working? It’s not your fault. According to geneticist Giles Yeo, your body is hardwired to hold onto fat—especially as you age. Yeo breaks down why your metabolism slows, how your genes shape your hunger, and why exercise isn’t the fat-loss fix you think it is. If you’ve been eating better, moving more, and still not seeing results… this is the science-backed reality check you’ve been waiting for. Listen to the full episode here - Spotify - https://g2ul0.app.link/y96HFbLIDSb Apple - https://g2ul0.app.link/9Ow3Z5SIDSb Watch the Episodes On YouTube - https://www.youtube.com/c/%20TheDiaryOfACEO/videos Giles Yeo -  Why Calories Don’t Count - https://bit.ly/3XWPtaL Gene Eating - https://bit.ly/3Yc37X6 Learn more about your ad choices. Visit megaphone.fm/adchoices

With my genetic makeup, how might there be differences in my genetic makeup that make my relationship with food and eating and weight loss different from yours? Oh, okay. I probably don't have as good an answer. Genetics does not have as good an answer about why different people eat differently, aside from cultural differences at the moment. Okay. So the genetics. The reason behind that is because it's very difficult to accurately determine what someone has eaten in order to do genetics. What we do know, because we can actually observe, is how people of different ethnicities are susceptible to different diseases. So famously,

East Asian people, people that look like me, South Asian people, Indian, Pakistanis, Bangladeshis, cannot get as large, BMI-wise, before becoming at risk of type 2 diabetes, right? Compared to white people, Polynesians, famously, who can get pretty large before they actually end up getting diseases. So that's a classic example where this is why South Asian people, East Asian people have a higher predisposition of diabetes even though obesity is not particularly a big thing in their cultures. But then you then begin to look at body shape. That does matter as well.

Where do you put your fat? Do you tend to put fat on your bum, on your tummy? You know, what is your, how tall are you? How short are you? And all of these things, which we can see visually, we can see, there are people who are then susceptible or not susceptible to specific diseases. Other things you can't see, okay?

Why are African-Americans, for example, more likely to end up with cardiovascular heart disease? Okay? Less likely with diabetes. Whereas why are Indians, you know, more and so that you then begin to ask the question and there we have genetics. What about in terms of this obese gene? I read in chapter two of your book that there is a gene for obesity. There are more than a thousand genes for body weight. The obese gene in chapter two of your book that there is a gene for obesity? There are more than a thousand genes for body weight. The obese gene in chapter two, which I talk about, is this leptin gene. It's this gene which lets your brain know how much fat you have. So that's the exact gene. Leptin is the gene that I'm talking about in chapter two with the obese.

It's called the obese gene because the mouse was called obese. There was a lack of imagination because the mouse was called obese, there was a lack of imagination, because the mouse was a naturally occurring mouse that had a mutation in the same gene. Scientists found out what that was and then found out that it was conserved in humans. And that's where my boss, Steve O'Rathley, then came in and found that that gene was also mutated in some humans. So that's the obese gene. It's the fat gene, fat gene, meaning gene from fat, that lets your brain know how much fat you have. And is that possible to be not just on or off, but slightly defective? So some people

can just get a little bit more hungry than others, or is it a binary thing where it can be on or off? So leptin, for whatever odd reason, is pretty much binary. So if you have a little bit of it, you're fine. If you have none of it, you're not. However, there is obviously, there is obviously a pathway leptin signals to the brain, which signals to something else. And there is a another gene that I looked at called MC4R. It's part of the pathway. It's part of the same fat sensing pathway. That is a rheostat, it's like a thermostat. And so for example, we have found thousands of different mutations in this gene.

And you can imagine that depending on the severity of the dysfunction, some are completely dead, some are 70% functional, we can predict how much someone will eat in a test buffet meal scenario if they have a 50% functioning gene versus a zero functioning gene. And we now know that 0.3% in this country at least, so 200,000 people in the UK, a million people in the United States will carry mutations in this MC4R gene, making them more likely to end up with obesity. So that at 18 years old, if you carry a mutation in this MC4R gene, you are on average 18 kilos

heavier, 40 pounds heavier at 18 years old on average. And that's 200,000 people in this country. So it's not super common, right? It's still 99.7% of the people's body weights not determined by this, but there are a lot of people's body weights who are dependent on this specific gene. But it is a tunable system.

So it's a little bit or a lot means that you are either slightly heavier or a lot heavier. So I'm thinking of some, you know, families often look quite similar in terms of body shape and size, etc. I'm wondering how much like control they have against fighting against those genes to get a six-pack abs, not saying that's a sustainable, healthy place to get to, but is it significantly harder for certain people, if their family is maybe a little bit more larger, to get to fight against that and get to a different state and then stay in that state.

Yes, undoubtedly. So there is certainly what we call, it used to be called a set point hypothesis, meaning that each of us has a weight we actually protect. It's probably more nuanced than that set range. There's a range that you can actually range that we find easy to keep to the weight. So in other words, I'm not thinking about my body weight at the moment and this is the weight that I am, but I wish I was half a stone or a stone lighter. But if I lost that half a stone, I would then have to think about food all the time to keep that half a stone off,

whereas I get half a stone more and I don't raise my weight anymore. So that's the idea, where there is a weight range that's easy to protect. And each of us is different. There are some people who are skinny, there are some people who just find it more difficult to say no to food than others. That's pretty much it. So some people's thermostat in food

is set a little higher than others. And you defend that thermostat, 25 degrees versus 20 degrees. And there's really next to nothing you can do. You can shift from 25 to 24 and a half, and maybe after Christmas, you're 25 and 0.5. Okay? And so you shift around there. But the likelihood of you getting down to 20 and staying there, you can get down to 20, okay, if you do some stupid diet. But the moment you ping, you ping right back up again. So we do defend, there is very, very little choice in inverted commas in where we end up with the body weight over a lifetime.

Any given meal, we have a choice, you think, right? Pizza or no pizza, pizza or no pizza. But over thousands of feeding events, there's very little choice. What then, you reference age there, do we get fatter with age? Because generally I look at, you know, I'd say younger people typically have a slightly leaner physique and then something seems to happen along the way. Is that just a false observation I have or is there some science that supports the gaining of weight as we age?

There's science. A, weight is inexorably up, okay, even though we've stopped growing when we're 18 years old. Actually, there's some latest science. I used to, if you would ask me the question five years ago, I would have said that by the time we hit 40 or 50, our metabolism starts to dip. That's part of the reason. That's not true. As it turns out, our metabolism doesn't start to dip till we're 60. Okay. But what happens as we get older are a number of different things. First of all, we tend to get richer, we tend to get more money. We tend to sit on our arse more, just in terms of the type of jobs we do.

And because of both of those things, we tend to exercise less because we're busier, and so we lose muscle mass. Those are all three things. Metabolically, the most active part of your body are the muscles. So when you're younger and you're doing things and you have more time to go to the gym, first of all, your metabolic rate is linked to the amount of muscle you have. And so as you get older, you're set on your arse, you eat a bit more, we don't eat less, we eat more, and we can buy richer food because we got more money, and you begin to lose muscle mass. So all of those things put together means

that you inexorably become larger. Then what happens at 60 years old, your metabolism then starts to drop as well and then you get even larger middle-aged spread, etc. So on that point about the more muscles you have, the higher your metabolism, that means if I've got big muscles, then I'm burning my food faster. Yes. Fantastic news. I'm going to work out later. I was really started by that. After I read it in your book about us gaining more and more weight as we age, I Googled it.

And the Healthcare Research and Quality Agency said that we naturally tend to gain weight as we age to the tune of one to two pounds per year, according to their review. And that's from the Agency for Healthcare Research and Quality, which I found quite startling. But completely accurate. So the numbers, so what the numbers that we have is,

I think that's right actually. So between 20 and 50 years old, those 30 years intervening, the average person, average, will gain about 15 kilos in weight, which is 32.2. Yes, two pounds a year, one to two pounds a year. 15 kilos in weight is gained over 30 years on average. Some gain very little, others gain a hell of a lot more. We look

at ourselves in a mirror. I look at myself in a mirror. But it's true. I don't want to be that guy. Mate, I don't know much choice you have. What can I do to try and stay? Because for me, it's not really about the weight thing or how you look. It's more about like, I don't know how to say this, but there was this big set of stairs the other day, really, really long set of stairs leading down to this lake. I was in Indonesia a couple of months ago and I remember thinking about those stairs and thinking, God, if I wasn't athletic and strong and didn't have good knees and things like

that, there's no way I'd be able to get down this long winding hand carved set of Indonesian stairs so that I could go on this boat trip that I was going to go on. And I just thought about how it was a weird thing. I know this is kind of a strange story to tell, but it crossed my mind. I got to the bottom of the stairs and I turned to the person I was with and was literally like, you know, that's why I've got to stay in shape for as long as I can, because I want to do these boat trips

and I want to go on this little rafting thing, but I won't even be able to access it unless I can go down up and down those stairs, like 200 meters of stairs down this cliff. So that's what I care about. I care about being active and strong and fit for as long as I possibly can. And I, from what you've said about gravity and weight,

being overweight is going to inhibit my chances of being able to do those stairs. So, I think there are two elements there. First of all, there is doing the things that we want to do. Okay, like that, because you're exactly right. These are the things which I can still do that. I can still walk up a mountain or down a mountain because I'm still fit enough to do that.

And I wanna stay as fit as long as I can to do that. And weight will inhibit that, undoubtedly. But then there's a second element to actually consider. Now that's healthy, look, none of us are going to live longer. We hopefully, and anyway, if we lived longer but was unhealthy, would you want to live longer? So you want to live longer but healthier for longer, okay. And undoubtedly, the thing that is closest related to health when you age is not your total weight. There's a role to play there. The amount of muscle you have is your muscle mass as you age, independent of how much fat you have, that will determine how healthy you are as you age. So now I'm talking about going into the 60s and the 70s

rather than when one is able to go down a 200 meter set of steps, okay? So now, as you get older, the most crucial bit of information is to maintain resistance training, not lifting. And that's not what I'm talking about. Sitting on a wall, getting up and down a chair, because that, the amount of muscle mass you have,

really, really, really marks the level of health that you're gonna get. And then the science is startling. It is so, so, so related, independent of weight, you know, from there. So muscle mass is the most important for healthy aging the moment you get 60, 70 plus. Interesting.

Okay, so I'll keep doing resistance training. Correct. Always keep resistance training. And lifting weights as long as I can. Lifting weights as long as you can. At some point you won't be able to live weights. Well, I don't know. Don't write me off. Don't write me off, Charles. The hubris of youth. Yeah. That's the naivety of youth. Yeah. You just assume you'll always be able to do what you can do now. I, I, yeah, it's something I think a lot about and I think a lot of people will

watch this podcast because probably, especially this time of year, we're in January, they'll probably be trying to find ways that they can cut fat. They want to be a bit skinnier. You said, you think you said half a stone you want to lose. I'm in the same place. I think most people want to lose a half a stone or something. What is the way that you would suggest to do that? The simple way, you know, not the like, like in complicated, go buy this guy's course and do three million sit-ups, whatever. The simple advice you would give someone that's hoping to create sort of sustainable weight loss. Okay. So this, this something's like the last page of, of the why calories don't count book, but it is something like the last page of the Why Calories Don't Count book, but

it is a set of numbers and I know I said not to count calories, but it's a set of numbers that you can apply to whatever diet you like. So the first is the amount of protein you eat, and you need to try and focus on trying to keep to about 16% of the energy in your day from protein. 16%. And there's a sweet spot. So if you eat too much and you're not lifting, you're stressing your kidneys because your kidneys have to get rid of the nitrogen from the protein. So 16% is a sweet spot.

And it doesn't mean steaks only. It can mean beans, tofu, any kind of protein from anywhere. 16%. Second is fiber. We need to eat as much fiber as physically possible. 30 grams we want to aim for. Although we're looking at the moment on average in this country, we're probably only eating 15 grams.

We need to double the amount of fiber we actually eat. Third, we need to limit the amount of added sugars into our diet. Added sugars meaning sugars not tied up in fiber. It's powdered stuff, maple syrup, algarve, nectar, all those are added sugars you put in. Keep it to 5% or less of the energy content in your day. And those are the three numbers that I want you to think about. So 16% of protein, 30 grams of fiber, 5% or less of added sugars.

Apply that to whatever you want, what keto, whatever you wanna do, apply that. And I think that will be a sustainable, healthy way to eat. Now there's been a lot said about exercise as a weight loss strategy. A lot of people think, you know what, I will just run every day and I'll lose weight. In your books you said,

the problem with using exercise as a weight loss strategy is that doing exercise makes you feel hungry. You can't outrun a bad diet. Is exercise a good strategy for weight loss? It is a good strategy for weight loss if you're an Olympic athlete or a Tour de France rider. What if you are a muggle like me? A muggle like you, a muggle like me, then exercise,

okay, exercise, you can never replace the goodness and wonderfulness and health benefits of exercise. Is exercise a good weight loss strategy for a muggle like Steve? No, it's a good weight maintenance tool though. So in other words, once you've lost the weight, which means you need to be less somehow, exercise helps you keep the weight off.

So once you've actually lost the weight that you're aiming for, whatever that might be, then do the exercise and that will help keep the weight off. But it's not gonna help me get the weight off in the first place. No. That seems to sit in contradiction to what my old personal trainer.

Only because we don't do it enough. So now if you had, okay, let's put it this way. Let's put it this way. The way that it would work is if you had a personal trainer and a chef, then what would happen is your personal trainer will make you work hard and your chef will make your meal. Okay. Therefore what happens is it's controlled on both sides. That is not typically what happens in the real world. I go on my run, my cycle, what have you. I come back, I'm ravenously hungry. I open the fridge and I stuff my mouth full of carbs.

That is my story, right? And so it is very difficult to control your diet after you've done long, hard exercise bouts because you get ravenously hungry. So professional sports teams, A, they exercise ridiculously, they train three times a day. So that's that. But they still have chefs and dietitians and they eat what the canteen puts up for them, which is healthy food. So someone is looking after their diet for them, but they are burning so much they don't have to worry too much about how much they eat, whereas we do. I know it's counter-intuitive in some sense, but it's purely because we don't exercise enough.

And is that also because, ultimately, because the brain is controlling our feeding behaviour? So the brain knows that we've just been for a run, so it's adding to our appetite a surplus to make us return to that weight it's trying to protect. There's that and there's also our own internal psychology on it. Because now you feel a bit smug. You say, oh, I went for my run on Sunday morning, you know, and then so I can eat what I want. And there's that element too. So suddenly when you normally would say, oh, I better not eat so much today. There are some internal controls that we sometimes have. Those internal controls are weakened once we've actually had our exercise,

because we feel that we have earned the food that's in front of us.