3 simple steps to transform your metabolism with Shawn Stevenson and Prof. Tim Spector

Only 12% of American adults are considered metabolically healthy, meaning the vast majority are at increased risk of heart disease, diabetes, and strokes.

But what exactly is metabolism, and why does it matter so much for our health?

You'll discover how poor sleep, stress, and ultra-processed foods impact your metabolic health and how this sets the stage for weight gain and chronic disease.

More importantly, Shawn and Tim will share the simple, science-backed habits that can improve your metabolism, from eating nutrient-dense foods to optimizing movement and sleep.

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Transcript

Jonathan Wolf: Shawn, thank you for joining me today. 

Shawn Stevenson: It is my pleasure to be here. 

Jonathan Wolf: And Tim, always great to have you here. 

Prof. Tim Spector: Me too. 

Jonathan Wolf: So Shawn, we have a tradition here at ZOE, where we always start with a quick-fire round of questions from our listeners. We have very strict rules. You can say yes or no, or if you have to, a one-sentence answer.

Are you willing to give it a go? 

Shawn Stevenson: I'll give it a shot. 

Jonathan Wolf: All right. Are most people metabolically healthy? 

Shawn Stevenson: No. 

Jonathan Wolf: Can you always tell if someone has bad metabolic health because they will be overweight? 

Shawn Stevenson: No. 

Jonathan Wolf: Is a faster metabolism better for your health? 

Shawn Stevenson: Not necessarily. 

Jonathan Wolf: And Tim, can the type of food you eat change your metabolism?

Prof. Tim Spector: Yes. 

Jonathan Wolf: Can changing how you sleep improve your metabolism? 

Prof. Tim Spector: Definitely. 

Jonathan Wolf: And finally Shawn, what's the most common misconception about metabolism? 

Shawn Stevenson: That it's just about converting food into energy. 

Jonathan Wolf: And it's not? 

Shawn Stevenson: Absolutely not. 

Jonathan Wolf: Well, I think that's a brilliant introduction into what we're going to get into now.

Firstly, we've never done a podcast specifically on metabolism. And secondly, I really don't understand what it is, despite the fact that the word has come up so often. So actually, I'd love to start right at the very beginning. Shawn, what is metabolism and why does it matter? 

Shawn Stevenson: From a rudimentary perspective, it's converting food into energy. But that's looking at energy through this very isolated, vanilla way. 

There's this entire microcosm of events, and metabolism is really about the sum of all the different pieces that can create and generate energy and that feed into each other. And for me, it's really based on the principle that energy cannot be created nor destroyed, it can only be converted from one form into another. 

And so this energy exchange, even if we're looking at that very vanilla version of it, food is creating energy. Where does the food come from? What are the pieces and parts of the food that create the energy? 

There are other things besides food that are getting converted into energy for us as well. Whether that's body fat, whether that is oxygen, and how it relates to all these different pieces. 

There are literally millions of parts and inputs that determine metabolism. It isn't just food and even from the perspective of food being used as energy, the endpoint being the mitochondria, which we'll get to I'm sure and talk a lot about.

When we eat a food it doesn't just become energy. It gets converted into a currency that our body can actually use. Our body runs on a certain currency. And so there's so much work involved in converting that food into the currency that our body can use. 

Sometimes that conversion doesn't happen. Right? Our body isn't converting everything that we eat into that currency that we're using.

Jonathan Wolf: And Shawn, could you talk me through that maybe in a very simple way, let's imagine I eat a piece of bread…

Shawn Stevenson: Let's use actually a good example since you mentioned bread. Alright, there was this fascinating study published recently in the journal Food and Nutrition Research. 

They had test subjects, and this is a crossover study, so everybody's doing both things, to consume a sandwich of either multigrain bread and cheddar cheese, or a sandwich of what they deemed to be ultra-processed food, which was white bread and cheese product. 

And here in the United States, Kraft is a big cheese company. That's what I grew up eating. But it's called Kraft Singles because they can't legally call it cheese. There's no cheese in the cheese. And so it's this kind of cheese product, right? 

So they had test subjects to consume both sandwiches at different parts of the study. Now, keep in mind, that these sandwiches have the same amount of protein, fats, carbohydrates, and the same amount of calories. 

But when they ate the two different versions of these sandwiches, very different things happened with their metabolism, and in particular, the expenditure of the calories they consumed. 

So when people ate the processed food sandwich versus the whole food sandwich, they had about a 50% reduction in calorie expenditure, or calorie burn, after eating that processed food sandwich.

Something happened, and to create a very simple understanding, it basically created metabolic clogs. It blocked the body's ability to use that energy efficiently and to get rid of it. 

And so what does our body do? It's gonna do what it can to protect us. And if even that means holding on to some of these calories to try to figure out what to do with this later at some point. And not to mention all the other pieces that come along with that. 

It's not just the calories from the food. As Tim knows this as well, there's a lot of other compounds that come along with ultra-processed foods. Whether this is dilates, whether this is pesticides, or all these other things that can disrupt our metabolism.

So, when it boils down to it if we can just kind of consolidate this whole idea when we're choosing to eat a certain food, it's not just this calorie conversation. Tim and I talked a lot about this when I had him on my show. It's so much bigger. There are all these, and this is the term I want to share with everybody, epicaloric controllers. There are these epicaloric controllers that are determining how our body is processing the food that we're eating. 

So, today we're going to expand from the conversation of just calories and understand that our metabolism, when it boils down to it, it is the conversion of food into energy, yes, but there are all these other really wonderful factors for us to pay attention to.

And today I want to help everybody to just refine it to some very simple ideas because it can be complex obviously, there's so many pieces to cover. But today I want to share some of the top things that are the epical or controllers that we can apply in our lives to make better choices and to have a more efficient metabolism overall. 

Prof. Tim Spector: That study you refer to was that short-term metabolism or long-term because I think people often get confused. Because in a way the long-term might be more important as the body resets, whether it's from exercise or eating. 

Do you want to try to help us through that? Because I always find that one of the hardest things when we talk about metabolism is this short-term reaction of the body and then what's the sort of, what's the long-term rate?

Shawn Stevenson: That's such a great question that only you would ask, of course.

What we're looking at here is exactly that. It was a short-term effect. So there's a 50% reduction in expenditure of calories in the short-term, but long-term, what does that look like? 

Well, the body's going to find a way to get rid of a lot of that energy. But there's this residual effect as you're doing that day, after day, after day. This kind of compounding reverses interests in a way, making it harder and harder and harder for us to have that long-term energy expenditure.

And so it's just taking a snapshot. And that's the thing about these studies. They're always looking at things in these snapshot moments and life is so much more dynamic. 

Jonathan Wolf: You looked at these two different meals, and they looked almost the same, in theory, they're bread and cheese, bread and cheese, but one is ultra-processed and one is much more whole grain and natural and real cheese. 

You're saying that metabolism is the way that you convert food into energy, but although both of them have the same number of calories, you’d think that the metabolism has to be the same.

You're saying that with this ultra-processed food, somehow your body's metabolism was completely different and it held on to a whole bunch of those calories and stored them as fat basically. Whereas with that more natural food, it sort of, it sort of burnt them up even though they were the same calories.

Did I understand that right?

Shawn Stevenson: We can't say that study doesn't reveal whether or not it's getting stored as fat per se, but the body is slowing down its processing of that energy. 

There's going to be a tendency, especially over time, that more and more of that's going to get stored as fat. But as Tim mentioned, in the short term, it can just be everything's kind of slowing down.

Your body, from my perspective, is just trying to figure out what to do with this stuff, because it is newly invented and based on the things we really evolved eating, where we have a level of efficiency, and our bodies are incredibly intelligent and resilient. So they can figure out how to process that cheese product if it's forced to, but ideally is that optimal? Probably not. 

Jonathan Wolf: I think the follow-on question that was one of the top questions that we had, was around metabolic health. So just as I think I'm still a bit confused really about exactly what metabolism is, I'm definitely also confused about what metabolic health is.

What does it mean? 

Shawn Stevenson: Metabolic health, and I love that this is a big part of the conversation today, because when I graduated from college, I studied nutrition, I studied biochemistry, and I was not taught about ‘metabolic health’, all right? It's just like, even in my first nutritional science class, we were, first of all, we were taught the food pyramid.

This was the nineties. My teacher, the professor was basically, he came in and he shared that if you want to lose weight, you expend more energy than you take in, right? As simple as that. If you want to gain weight, you consume more calories than you expend. And that was it. If you want to stay the same, they need to be the same.

And a little side note, and I don't talk about this often, but my teacher was significantly overweight. And I'm not saying that this was a character flaw or anything like that. I'm sure that he was doing a lot of things that he was trying to teach us, but they just simply weren't working for him.

And he just needed, in his mind, I just need to cut more calories, I need to do better. And we start to punish ourselves because this dogma that we've been taught isn't working out. And it does work for some people. It does work for some people. Because at the time he's teaching us and he's applying, we need to eat 7 to 11 servings of ‘healthy’ whole grains every day and that's the basis of our diet. 

So some of the principles that I took from that is basically, if it's white, it's not right. So no more refined carbohydrates. I'm not going to eat this regular pasta that I grew up eating. Let me get whole wheat pasta. Right. 

I'm not going to eat the white bread that I grew up eating. In the United States is like Wonder Bread and Bunny Bread and now I'm going to eat whole-grain bread. 

I'm gonna eat a lot of brown food and this is not taking into account my unique metabolic fingerprint, right? So these are some of the things that go into our own unique metabolic fingerprint in our own unique metabolic health. 

Part of that is our own unique microbial fingerprint. What if somebody has a hard time with their microbial makeup, trying to process a lot of these ‘healthy’ whole grains? What is that going to do to their metabolic health? What is that going to do to their energy assimilation and expenditure? Right? 

All this stuff matters and we can't have this kind of cookie-cutter approach to things. And so, an example that really stayed with me for years that I couldn't understand and I would go to this Chinese food restaurant that was right off campus. And I was wondering why the store owner and their family, I would go around the time when they're having their lunch and they were eating white rice and steamed vegetables and I'm just like, why are they eating white rice? Don't they know that this is so much better for you to eat brown rice?

What it was truly, if… my wife is from Africa as well, she's from Kenya. And they've been eating white rice for a long time. Yes, there can be parts of the container or the brand of certain things that can add fiber, but they can also be a gut irritant for a lot of people as well. 

So I think some people, our ancestors figured out centuries ago that if we want to efficiently process this food without side effects, if we're looking for caloric energy, right, if that's our goal with this thing, we might want to get rid of this because it can create some gut irritation for some people.

So getting that background education and not being taught what metabolic health is, which is what is right for me right now to efficiently process my food to feel good. Of course, body composition can come into the mix as well. It's out-picturing and you're opening rapid-fire question was, can we have out-picturing of fitness and still be metabolically unhealthy?

Absolutely. But it is a part of the equation. There are all these different parts. And so, ultimately, and the most recent data here in the United States, I think that the number, of course, can shift a little bit, but I think it's pretty close, only 12 % of United States citizens are metabolically healthy.

Jonathan Wolf: Only 12%? 

Shawn Stevenson: Only 12%. That should be outrageous, blow our minds. But the question is, again, this is what we're talking about, what does that mean? What is metabolic health? 

Well, in this particular study, they were looking at triglyceride levels. They were looking at HDL and LDL ratios. They were looking at, yes, body composition, body fat percentage, and things like that.

But it's still looking at things through a very small frame. So I'm not going to be the guy that comes on this show and tells you, this is exactly what metabolic health is. 

Prof. Tim Spector: Shawn, I have this problem writing books to the public to try and explain metabolism. My editor says, what is metabolism, metabolic health? 

Well, the best way I described it and I’d love your thoughts on it, is it's the energy management system of the body and its efficiency. It's how all the bits in the body work together and how efficient it is. Or whether it's inefficient and it's having to work too hard to keep the house warm or cool or whatever it is. It’s keeping it exactly at that right temperature all the time, regardless of what you're doing.

Do you think that's a reasonable way to describe it? 

Shawn Stevenson: Absolutely. Efficiency is such a key word in this, but that can be misconstrued. Because we can be very efficient in converting that white rice into glucose and shoot up our blood glucose, have a huge response from insulin. Yeah, it's efficient to convert that into energy, but is that metabolically healthy for us?

And so we've got to take into account that efficiency means multiple things as well. 

Prof. Tim Spector: Yeah. It means not having side effects and means not having other things happen to the system that make it go wrong. I guess 

Jonathan Wolf: I was just thinking that you were talking about the, you know, the white rice and then the brown rice and the white bread and the brown red.

And both Tim and I have both done the ZOE testing where it was part of it, to get your own blood sugar [tested] and probably, many of the listeners on this podcast have also been members and done that. 

I think one of the things that I remember being most shocked by was a whole bunch of things that I thought were really healthy because they were brown. So the first time I ate brown bread I spiked my blood sugar so much. And like Tim, my wife's blood sugar spiked a lot less than mine, which was sort of annoying.

Brown rice, off the roof. So I definitely have had that personal experience you're talking about how your metabolism is dealing with this not at all in the sort of nice easy way that I had always assumed because I've been told that this stuff was sort of fine for me. 

Shawn Stevenson: Yeah, and that can be explained through a number of mechanisms, right? One could be inflammation. There could be this inflammatory response that's causing some disruption with how your body's handling that.

That reminds me of a study. This was conducted by researchers at the Albert Einstein College of Medicine recently. And this is a huge issue that people are talking about in relationship to metabolism, inflammation yes, but specifically neuroinflammation.

These researchers were looking at hypothalamic inflammation. So the hypothalamus is kind of glorified as a master gland in our brain that's controlling a lot of things downstream. It's an integration of our nervous system and our endocrine system, so our hormones and also our nervous system. 

What they found was that people who had inflammation in their brain, hypothalamic inflammation, had the accumulation of more belly fat and body fat downstream and a higher level of insulin resistance.

Now here's the catch, people with more insulin resistance and more body fat also had higher rates of inflammation in their brain. So it's like this vicious circle that's creating all this metabolic unrest. So their metabolic health is suffering because of inflammation in their brain. But it's a chicken or the egg scenario, which one came first, you know, which one's causing which?

And of course, I'm holding back on sharing solutions right out of the gate, but I got to share one really quickly, if that's okay, I got to share one. 

Prof. Tim Spector: You couldn't wait.

Shawn Stevenson: So some researchers at Auburn University, here in the U.S. found out that there's this really remarkable food that can help to address this neural inflammation.

It's a food that's been used for thousands of years, of course. And it's oleocanthal-rich extra virgin olive oil. They found that it was able to reduce inflammation in the brain, specifically helping to repair and support the blood-brain barrier. 

Part of the reason this inflammation epidemic is happening in the brain is that things are getting into the brain that shouldn't be there. There's a breakdown of the blood-brain barrier that's happening because of the environment that we live in. 

We could get into all the different reasons why, but it's mayhem. And if people are wondering, is my brain inflamed? Chances are, yes, especially if we're not metabolically healthy. And the question would be, well, why doesn't my doctor know this?

The brain is very protective, this isn't something that you're going to notice per se unless you have very, very sophisticated imaging and all these different tests done. It's just a place that we're not looking. 

But I'm telling you right now, and people that are listening to a show like this, they're always ahead of the curve. And so you're going to hear more about this in the years coming up, I'm sure about neuroinflammation, the downstream effects with metabolic health, and also body fat causing more neuroinflammation. 

Jonathan Wolf: And you're saying the magic properties of extra virgin olive oil on the brain as well as in other things that might have been studied before.

Shawn Stevenson: Yeah. And one of the benefits of that extra virgin olive oil is it tends to be anti-inflammatory. Yes. 

Jonathan Wolf: You mentioned a few minutes ago this idea that only 12% of adults in the U.S. are metabolically healthy, which is an extraordinary number. And I know that across Europe and the rest of the Western world, these numbers are not very different.

I'd love to understand what that means. And Tim, you're a doctor, what does it mean if someone is metabolically unhealthy, for their long-term health? 

Prof. Tim Spector: Well, classically, it's been associated with many common disorders. So, the main one's been type 2 diabetes. So, you're much more prone to have type 2 diabetes if things are unstable in a way.

And that just means that the amount of insulin you're producing, relative to the amount of sugar is out of kilter. And therefore, there's more stress on the system. Therefore, you're more likely to end up with type 2 diabetes. 

It also means you're more likely to have an increased risk of heart disease, increased blood lipids, and inflammation in your arteries. Your blood pressure is more likely to be raised, therefore you're getting hypertension and then get strokes, et cetera. 

Increasingly, it's also been linked to brain disorders as we're discussing. The big one at the moment is the increase in dementia, which has also been termed as type 3 diabetes because of the increase in both conditions in many countries. 

So, having a disordered metabolic condition really predisposes you to all kinds of conditions. And there's probably many more that we don't yet associate with it just because your basic system is not functioning properly, which means that the rest of the body is struggling to keep up as well.

So as well as these individual problems that we're seeing with glucose and sugar and insulin and blood vessels, the whole system is just working too hard, I think is the way I see it. Therefore your body can't repair itself as well as it could otherwise. And also you get this other problem of inflammation coming in, due to the fact that your basic energy system is not really on its top game, it's starting to wobble.

Jonathan Wolf: I'm trying to think of an analogy. I haven't got a very good one, but I know the oil always needs to be topped up in my car. It's one of those things that they do when they check on it, in order for it to run fine. And my car runs these days for 10, 12 years without anything going wrong anymore.

But if for some reason I let all the oil run low and I keep running it and I know I'm sort of causing all this damage to this car and something's going to go horribly wrong after three years or four years. Is that how I think about it? It's not like this big collapse immediately, it's ongoing damage. 

Prof. Tim Spector: Well, whether it's your car or it's the boiler in your house, that's leaking, in order to keep your house heated at the perfect temperature, you're having to sort of put more fuel in, it's less efficient and every now and again, it's going to break down and cause other problems.

I think that's probably more of the way to see it and you might end up with rust in the system and things that wouldn't happen if it was really in its tip-top state. 

Shawn Stevenson: But therein lies the problem with trying to consolidate metabolic health into… Is it the oil? We've got engine coolant, we've got gasoline to run your car. We've got even the windshield wiper fluid could be a problem if it starts raining, right? It's all of these factors that are impacting the performance of our human vehicle, right? 

So we can't consolidate it and wonderful researchers are trying to. That study that I mentioned with the 12%, right, we're looking at cardiometabolic factors. But what about how your body is handling insulin and blood sugar and all these different things? But none of these things are happening in a vacuum. And they're all affecting each other at the same time.

There isn't a cell in your body that's not being affected by the activities of all of your other cells. We have trillions of cells. And it's a cellular community. 

Jonathan Wolf: I like this idea. All your cells are working together in harmony. These systems are working really great.

What are the simple things that have changed that means that now you're describing almost everybody as not being metabolically healthy, and presumably a hundred years ago they were? What are the key things? 

Shawn Stevenson: To use one word to kind of encompass, it's the environment. The environment that we're existing is very different than a hundred years ago, very, very different.

And whether this is the environment exposure itself, you know, there are billions and billions and billions of newly invented chemicals that are released into the environment here in the U.S. alone. And this is allowed, by the way, by the EPA, the Environmental Protection Agency, supposed to be protecting us.

And that's the thing too, we are a part of the environment as well. We tend to separate humans and environment. We're a part of the environment. And so just the air that we're breathing is different. 

Recently I was having a conversation about these PFAS chemicals, these forever chemicals that are just a part of our lives today.

Prof. Tim Spector:  Are these ones on Teflon and the frying pans and cookware and things? 

Shawn Stevenson: DuPont. Thanks to DuPont. This is back around the 1940s and Teflon, which again, just look at this incredible innovation. 

But now the result of that, the fallout of that is that 98% of people tested on planet Earth, I'm talking about from Alaska to Hawaii, 98% of people now have DuPont's chemicals in their blood. 

The researchers had to go back and look at blood from pre that time, and it was from soldiers to find blood that was clear of these compounds. 

And so the air we're breathing, the chemical exposure, whether it's through cooking and the fumes, and this is going back to another thing about our metabolic health and energy we're using. It's not just the things we're eating. It's also what we're inhaling as well is used as energy and conversion. 

And so obviously the food, our food culture is very, very different than our ancestors. I've been talking a lot about this and shouting this from the rooftops and one of my latest projects really helped to create a shift in this conversation.

My book Eat Smarter a few years back and talking about this processed food environment, ultra-processed food environment. And according to the BMJ, actually, over 60 % of the average American's diet is now made of ultra-processed, newly invented food. But the numbers are even worse for U.S. children. This was published in JAMA, the Journal of the American Diet.

Prof. Tim Spector: And even worse for U.K. children than U.S. ones, most recent data. 

Shawn Stevenson: Oh, yeah and this is the thing. As that's being implemented deeper into the culture, it's just going to get worse and worse. So about 70% of U.S. children's diet is made of ultra-processed, newly invented food. And that number is just continuing to climb. And this isn't just a U.S. phenomenon, obviously. 

But the question is, what is that? What are ultra-processed foods? Humans have been processing food for a very long time, just to be clear. If you're taking that olive, olive oil, for example, where does it come from? We're doing a process to get the olive oil out of the olives. But traditionally, it's a cold process. It's a stone process. You're smashing the oil, collecting the oil. It's very simple, right? 

Ultra-processed foods, on the other hand, are when you have a field of corn that somehow gets turned into a box of lucky charms. It's so much perversion and things that happen, all these different chemical additives, the processing of even creating this genetically modified weird corn in the first place. 

But for us, and I grew up in, a glorified food desert here in the United States, this was just food,  I didn't know that it was bad for me. It's just what we were exposed to and it's cheap. It's very tasty as it's designed to be. And for us, it's just food. 

I didn't know that there was a difference between say, wild-caught salmon and fish sticks. You know, I didn't know that there was a difference and so I'm going to prefer the fish sticks with copious amounts of ketchup, by the way, 

Jonathan Wolf: I'd love to bring Tim in here, both specifically here I guess we're talking about these ultra-processed foods and do they impact metabolic health? And then I think also as Shawn was talking about quite a number of different ways that might be affecting our metabolic health. 

I'm curious, as you're thinking about these, what are you most worried about? As people think about this, what should they be most worried about to think about themselves and their children? 

Prof. Tim Spector: For 20 years, I was studying genetics and there's a lot of data showing that genes are important in modifying our metabolic health and where we put the fat and the internal fat and we've discussed this before.

So, I believed that genes were really important. But what's clear is the last 50 years where levels have skyrocketed, our genes haven't changed at all. So our genes were really well adapted for the environment our ancestors had. And that meant we had the right energy control to get the right blood pressure, to have the right amount of fat on our body, to be able to process foods correctly.

And now we're getting this onslaught of not only pollutants but all these ultra-processed foods that our genes really weren't geared up to deal with. And also the abundance of food, the fact that there is unlimited food, which our ancestors never really had. So I think it's the inability to deal with the abundance and the different types of food that are causing this problem in most of the population. 

What's interesting is that there do seem to be some people in all populations who are protected against this. So even in the most obese countries, you'll find about 25 % of the population that can stay slim and we don't really understand why that is. But everyone else has ballooned over the last 50 years.

So I think we have to really have a hard look at what we were hardwired for, our system, and try and get back as close to that. Which means not only changing what we're eating, but also our patterns of eating.

So going from our current six episodes of eating every day back to perhaps what our ancestors were doing, is two large, substantial meals. Also our exercise patterns, not being sedentary, and better sleeping patterns. 

All these things that would then get us back on the same wavelength as our genes have determined the way for our energy to be stored in metabolism, to be working maximally 

Jonathan Wolf: Do we understand how these ultra-processed foods can end up damaging your metabolism? Because I think, I'm listening to this story that says it's not as simple as you're eating too many calories.

I think that was where you started Shawn, right? And there's all of this food that is just profoundly different from anything we had before but do we understand at all how this works? 

Prof. Tim Spector: We know there are a number of potential mechanisms, do disagree with me if you think Shawn. But I don't think we know which ones of them are the most important. 

We really haven't done enough study on ultra-processed foods. It's like a taboo subject mainly because Big Food has managed to lobby the government to make sure that in the U.S. and the U.K., we're not doing enough research on this because we can't touch cheap food. That's for the masses, that's political, we can't go there. 

But there are a number of possible mechanisms. One is the speed at which you eat is much different with ultra-processed food. So it might bypass some of these evolutionary mechanisms for feeling full. So that's one, all our ancestors would have taken much longer to eat that food, therefore, feeling full, those signals would have come in, which they don't come now. 

Then you've got the softness of the food, which means that you don't trigger. It's like baby food we're eating. So your jaw doesn't get the same workout. And there's evidence that the jaws of children now are receding. 

I don’t know if you've seen this, that dentists are very worried that over every 10 years, our jaws are getting smaller because they're just not used to actually eating real food.

Jonathan Wolf: That's crazy. You're basically saying that it's like you're not working out your jaw muscle enough and your jaw is actually not growing. 

Prof. Tim Spector: Yeah. Many people actually spend their whole life eating baby food now.

Shawn Stevenson: It's this phenomenon, it's called vanishing caloric density, right? So we have these foods like a Cheeto, for example, and it's so robust when you first bite into it, then it disappears. And it gives us an illusion of crunch and density. So also we'll continue to eat a lot of it and overeat it. And it's designed to be that way.

Because the way that we evolved, we have certain senses and receptors that are very sensitive to flavor and overabundance of flavor. And so it's them designing the right amount of intense flavor, but then to be able to back off with other compounds and just put it at this right level. 

Also if we're eating a ‘real food’, there's a certain amount of chicken that you might eat. And you're just like, I'm done with this chicken, I can't eat another bite. Or the same thing would hold true, you know, with eating an avocado per se. As we're eating a real food, our bodies start to rebel against it. Like that's enough. I've had enough. 

It doesn't happen like that. The ad is literally, I bet you can't eat just one. That's the Frito Lay mantra. Alright? They're literally saying, you can't just eat one of these chips. You're gonna eat the bag and you gotta fight yourself to stop eating it. It's designed to be that way. It's brilliant. But it's also kind of like a Dr. Evil level of brilliance. 

Jonathan Wolf: It's sort of terrifying, isn't it? The way you describe it is like, we've carefully designed this, so you're going to be unable to stop eating it. 

Prof. Tim Spector: We're going to beat your genes, yeah. All that evolution is worthless. You're powerless in our control. 

And of course, the chemicals in these products themselves have effects on our body that, again, our genes and evolution haven't prepared us for. So many of them are totally artificial in that they come from the petrol industry for most of the artificial sweeteners. They can disrupt the gut microbes and they produce chemicals that can themselves cause diabetes in other animals and send off anti-metabolic signals to the rest of the body.

When you eat some of these junk foods that Shawn's talking about, they regularly contain artificial sweeteners, emulsifiers, and preservatives, and these are not things our ancestors ever encountered or we have genes evolved to. 

So, when they get down to the level of our gut microbes, who would normally be processing them, they encounter them, they bash into them, and when they see something like an artificial sweetener, they produce chemicals in response to try and break it down.

They can't break it down, but the chemicals they produce can go on and make you more likely to get diabetes. They can send signals to the rest of the body saying there's something going on here. I don't really understand it. It's like an alert signal. It forms inflammatory signals or it stimulates the immune system, or it messes up the metabolic system.

And that's what lots of basic research has shown. You get similar effects with emulsifiers, which glue some of these products together. These potato chips and things always contain these glues to make it look like real food. And when your microbes encounter them, you get similar results. 

They can clump together, so they don't work very well. They get stuck together. And these emulsifiers also affect the gut lining so that you get leakiness of bacteria across into the blood and that can cause other metabolic disturbances. 

So these are just a few of the possible ways in which our bad food environment is messing up our energy management system, and our metabolism, and that's why we're in this mess.

Jonathan Wolf: We talked about a number of different causes behind this metabolic disease. Do you think that food is the number one or how do you think about that? 

Prof. Tim Spector: Yeah, I see it as definitely the number one obvious one that's really changed. I think, yes, there are these pollutants and plastics, but we don't yet know how much of a problem they are.

We know they're a problem, but we don't know how big it is. We should be very wary about it, but I think we do know enough about ultra-processed food now to know that is a definite real problem for everybody. These other ones, we're just starting to get information on them. 

Shawn Stevenson: I'll give you a very explicit reason why food is the number one. It's because all of our tissues are made of food. Every single one of the trillions of cells that I mentioned is literally made from the food that we eat. 

So we're determining what we're making our tissues out of and also the energy that our bodies are running on is made from the food that we're eating.

And so, if we've got, our mutual friend, Will Bulsiewicz, who, he went to school for like, forever, you know, 15 years or something to be a top tier gastroenterologist. He was not taught that when he's looking at his patient's gut health, or looking at, there's the stomach, the large intestine, the small intestine, that all of those organs are made from the food that his patient has eaten.

So the organs responsible for digestion, assimilation, and elimination are made from the food that the people are eating itself, right? Cardiology, same thing. We've got these experts looking at the heart health and the cardiovascular health of their patients. I know the very best in the field, these are my friends and colleagues, they're not taught that when they're looking at their patient's heart or their arteries or their veins, that they're looking at their patient's food that they've eaten, let alone what the blood is made of, and the list goes on and on and on.

So that's why food is so powerful to affect change is because it's making all of the parts. So if we are going to improve our metabolic health. We've got to make our parts and our energy out of the best things possible. 

Prof. Tim Spector: What do you say, Shawn, to people that say it's not about food, it's we can just tweak the mitochondria. Mitochondria, Jonathan, are these little bits of the cell that, we call them the batteries of the cell.

And so all our cells have these little mitochondria and they have their own set of genes and things. And there are many people out there who are selling products to enhance your mitochondria. And if you just tweak those mitochondria just a little bit, give them a little 5 % more, we can reset everything.

I'd be interested in your views on that, rather than this more holistic view that we've been talking about. Do you think there is a quick fix through our mitochondria? 

Shawn Stevenson: I'm sure there are things that can affect the efficiency and health of the mitochondria at a micro-scale.

But it is this whole system function, by the way, just to get some context with the mitochondria, about 10% of our body's mass, about 10% of our weight is made of the mitochondria, right?

We have a ton of mitochondria in our bodies. And so there isn't one thing that is going to fix all of that and make it run better. And keeping that in mind, the mitochondria are really the end destination for certain processes to take place, right? The ‘burning of fuel’.

But even with that, even with that, there are so many steps preceding that, and there are so many steps after. Because if we're just talking about in the context of ‘burning fat’, well, I was taught in school, lipolysis, which is the freeing of the fat to be used as energy, but it still has to make its way. It still has to make its way to the mitochondria, right? 

We can't just address the mitochondria. We've got to address all of the efficiency of this energy getting released to even get there and to be used in the first place.

Jonathan Wolf: I'd love actually to talk about what can our listeners do and what are the actions. 

Before we talk about food, you actually wrote a best-selling book called Sleep Smarter. Is there any role for sleep within improving this and maybe just help us, if we were going to try and run through now, what are the things you can really do?

What would you be saying to that? 

Shawn Stevenson: Absolutely. So sleep is another one of these epicaloric controllers or epigenetic controllers. 

I think the best way to paint this picture is from scientists at the University of Chicago, they did a ward study, in a controlled setting, a crossover study, looking at how does our sleep impact our metabolism. 

So they had test subjects to get an ample amount of sleep for about two weeks. So this was eight and a half hours of sleep, but they put them on a calorie-restricted diet just to monitor weight loss and body fat loss as well. And so, yeah, they collected all the data.

Another part of the study, again, it's a crossover study. So they have a washout period. Now they sleep deprive them. And they put them on the same diet and different test subjects are doing different things at different times. And it's a controlled environment. They're eating the same amount of food, the same amount of calories, but now they sleep deprive them. And they're only getting five and a half hours of sleep. 

Collect all that data for about two weeks. After they compile the data, when test subjects were well rested, they lost about 50% more body fat mass doing the same exact thing. They're eating the same amount of calories, but by getting more sleep, they lost more actual body fat.

If we're looking at this through the lens of metabolic health, the metabolic health was improved when they were getting better sleep. Now, here's a part of the study that I don't talk about a lot, where is that energy coming from when they're losing weight, where's that energy coming from?

When they were sleep-deprived, they were losing more muscle. Upwards of 60% more of the weight loss, because they were in a calorie restriction, but they were losing more of their muscle tissue, which is going to make you more metabolically unhealthy long term.

So our sleep has a huge, huge impact on our metabolism, and it might be, outside of the food itself that we're eating the other major controller for us to pay attention to. 

Jonathan Wolf: And Shawn, is there one thing that I could do to improve my metabolism that I could start doing today? 

Shawn Stevenson: There are dozens of things, of course, but if I was to consolidate it down to, I could do two really quick.

Number one would be, what is the biggest disruptor of our sleep today? Factually, it is our technology. So the number one thing in the environment that I would recommend people do, we've got tons of data on this, if you're on your screen right before bed, that light that's shooting into your brain is throwing off your circadian clock. 

Every cell in your body is getting out of sorts and just trying to figure out what time it is. Because we evolved being connected to this 24-hour solar day. And so we have this artificial daytime, essentially, when we're on our devices right before bed. And it suppresses our melatonin and increases our cortisol.

So you could be physiologically exhausted and just pass out, but you're not going to go through your sleep cycle efficiently. So, my recommendation, give yourself a little bit of a tech curfew. Now, again, I know that we're adults and we don't like restriction, even the word curfew still brings up bad feelings for me, but giving yourself a little bit of a screen curfew.

But here's the rub, we cannot take away something that is so attractive for us like our cell phone, like Instagram, and all these things that are designed to keep us hooked and entertain. We've got to replace it with something of equal or greater value. That's the key. And so what can you put in that place that 30 minutes or an hour, if you want to get crazy, off your technology?

This is what is going to be unique to you. So some people love to read, you can read a physical book, they still exist. You can listen to an audiobook or podcast. 

Jonathan Wolf: I'm guessing I can't just eat chocolate. That's not the right swap. 

Shawn Stevenson: I mean, chocolate, Tim knows this as well. The quality of the chocolate, there's some good chocolate out there that can be beneficial.

Jonathan Wolf: He always tells me off for wanting to eat it at 11. So I like the idea that you're now telling me that in order to put my phone away, I'm allowed to eat my chocolate.

Prof. Tim Spector: No chocolate on your pillow. 

Shawn Stevenson: As a matter of fact, having a cup of maybe some hot cocoa or cacao with some reishi mushroom, which has been found to improve our REM sleep, non-REM sleep, and overall sleep time. That's a good idea. And I've been known to do that a time or a time or two. 

Because there's these precursors in cacao and chocolate where it comes from, like tryptophan, that help convert into melatonin down the road. 

So the screen curfew, fill that with something of greater equal value time with your significant other. Maybe some intimate time, fill it with something that feels good. 

The second thing would be to control your environment that you're sleeping in and to create a sleep sanctuary. The human brain is always looking for automation. And so if you're going into a room to you want to go to get some great sleep, but you're getting into your bed and this is where you do a lot of your work, it's where you do a lot of your scrolling, your brain is going to be looking for that behavior. 

So make your bedroom tech-free to the best of your ability and make sure that you get… here we've got some blackout curtains around, but if you got external light pollution, some researchers at Cornell University found that just even putting a light behind the test subjects knee was enough to disrupt their sleep cycle.

So our skin has photoreceptors as well. So get the room nice and dark. And cool, and to the best of your ability, keep the technology out of your bedroom, make it a sleep sanctuary. 

Jonathan Wolf: So Tim, what are the best foods to support our metabolic function? If you were going to give us a brief outline for someone, what actual advice someone might be able to take?

Prof. Tim Spector: We know that you need to avoid foods that are really going to peak your blood sugar and stress your insulin levels. For many people, changing their breakfast, so not having their normal morning cereal or granola, not having their orange juice, which they would otherwise think is healthy, cutting out fruit smoothies that they've been told are super healthy.

So changing in a way what you believe is healthy food, and this is what people learn when they would do the ZOE program. But I think cutting out their sugar spikes is probably the number one thing for metabolic health if you had a tip.

Which means that you should replace those generally with higher fat foods, good quality fats, obviously, and plants that have high fiber content so that you're dampening down any sort of sugar spikes, particularly if you're prone to this or there's metabolic diseases in the family. 

Jonathan Wolf: And so Tim, what's your go-to breakfast? 

Prof. Tim Spector: My go-to breakfast is a full-fat Greek yogurt mixed with milk, kefir, and with berries from the freezer. And I generally use the ZOE daily 30 mix now on top of that to give me extra fiber and lots of different plants. 

Jonathan Wolf: Amazing. I have so many more questions but unfortunately, I have hit time, so I'm going to try and do a quick summary on what's quite a complicated topic, and Shawn and Tim, please keep me honest.

So the biggest thing I'm taking away is that only 12% of Americans are metabolically healthy, and you're saying that that number is very similar if you're in the U.K. or Canada or wherever. 

And that's a problem because your metabolism is what's turning food into energy. And if it's not working well, actually, the end result is either lots of very serious diseases, but also weight gain and all the results that we see around us.

I think the other thing I take away is the culprit seems to change a lot. You both talked a lot about ultra-processed food, and I never heard anybody talk about ultra-processed food when I first started with Tim eight years ago so that's a really profound change.

Shawn, you shared this amazing study where you were saying literally you had people eat exactly the same sandwich right but one was a regular sandwich like my grandmother might have eaten, and this other one is this artificial bread and this artificial cheese-like substance. And you're saying they actually found that your metabolism slowed down by half with this ultra-processed food. 

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So exactly the same number of calories. It looks the same on the outside, but your body is responding really differently. And I think it's another example about how just thinking about calories clearly doesn't help us to understand what happens and how the food we're eating is having this profound impact on us in a way that I think many of us didn't realize.

Then I think we talked about ultra-processed food and the way that it affects us. One of the things you both talked about is the way that it's like baby food. So you eat it and it you don't even realize you're full and it gives you this intense flavor but then it disappears, you have to keep taking one. 

These companies even proudly advertise the fact that it bypasses all your controls and you just can't stop, so there's something quite wrong about that.

And then Tim you explained that for you, a lot of the reasons why you think now this ultra-processed food is so harmful is the way that it sort of messes up our microbiome. I have to say when you describe the food being full of glue, I don't know about you, but I don't really like the idea that my food is full of glue. 

It's definitely not a big ingredient that they put on the front, but these glues and sweeteners are somehow affecting the microbiome and they can't cope with it and then it's sending these chemicals that are sort of messing up our microbiome. 

But then we did come to some really positive actionable advice. I love the fact it's not just about food. And so Shawn, I think you said sleeping better, that these experiments show that sleeping better can have a profoundly positive impact on your metabolism.

And you said, if you were just going to pick two, so you have a whole book, I'm sure with many more clues, and we'll have a link to that in the show notes. But if you want to think about two. Tech curfew, so get the screen turned off before you go to sleep, but be honest, no one likes a curfew so you need to replace it with something better.

So how do you find something else to do? In the half-hour before you go to sleep, that sort of unwinds. And I think I'm going to really think about that. I think that's really interesting. I'm also going to make sure my wife listens to this bit cause we have a constant row about the fact that she brings her phone into the room and she will never listen to me, but maybe she'll listen to you, Shawn.

And the second one is sleep sanctuary. So don't associate the place you go to sleep with where you're working, keep that separate. Otherwise, your brain is going to start immediately thinking about things, which I love as an idea. 

Then we came back to food and Tim, you said your number one tip for metabolic health actually is to avoid foods that peak your blood sugar. That actually, that spike in blood sugar and collapse is the very particular thing that you're concerned around metabolic health. 

That means you really want to swap out foods that are leading to these really big blood sugar spikes. And we talked about some of those earlier in the conversation that actually just because they're brown doesn't mean that they don't spike your blood sugar.

And that what many of us who are in our forties or over, are taught about this food pyramid is full of foods that we're told are healthy. But actually, if you eat a lot of brown bread, you're going to have these big spikes, so you just need to moderate that. 

The biggest place to fix this is your breakfast because many of us don't realize just how bad our breakfasts are for us in terms of those blood sugar spikes. So, if you want to be like Tim, then you want to have much more high-quality fat rather than this low-quality carbohydrates. And so you went full-fat Greek yogurt, and kefir, and berries, and Daily 30 to add all the right plants on top. And that powers you through to lunchtime? 

Prof. Tim Spector: It's done pretty well so far. Yep. 

Jonathan Wolf: Shawn, thank you so much. I can tell there's many other things we could have covered. So I hope we can get you back in the future. 

Shawn Stevenson: It would be an honor. This has been awesome. 

Jonathan Wolf: Thank you so much. It's been so much fun. Tim, thank you also.