Doctor Tim Spector: The Shocking New Truth About Weight Loss, Calories & Diets!

Exercise doesn't help weight loss. The reason exercise doesn't work is because... Professor Tim Spector. He's an award-winning scientist.

Best-selling author. And he is ranked in the top 100 of the world's most cited scientists. We're going to be talking about the future of personalized nutrition. Many consider you to be the leading expert on gut health and diet.

What's your view on the ketogenic diet? Virtually impossible. What about vitamins? Waste of time.

What are the facts around fasting? No idea. Oh, shit. What do you mean, no idea?

The food industry wants you to focus on calories, fat content, sugar, so you don't have to think about the quality of the food. There's never been any long-term study showing that calorie counting is an effective way to lose weight and maintain weight loss. This is why I want people to think about food very differently than we have done in the past. So what is the cost?

Depression, anxiety is intricately linked to the quality of your gut microbes. These are microscopic bugs in our intestines. All of them are able to pump out chemicals that are vital for our body when they're fed the right foods. The reason we're in this space is we've killed off a lot of our good bugs.

I think people don't think of all the positive benefits that they don't think that you need to build them up. God, it's so confusing. You know, when you walk down the aisle in the supermarket, everything is trying to pretend that it's good. So how do I know what is good?

You have to... Tim, many consider you to be the leading expert on topics relating to gut health and diet and food, et cetera. But how would you describe your own professional academic bio? What is that bio in your own words?

It's complicated. So I've changed form over the years quite a lot. And I'm quite unusual in terms of academic medics who usually stick very strictly to one specialty all their career and fear to go anywhere else. So I was at medical school, did the usual stuff, then wanted to be a physician, then did rheumatology.

What's rheumatology? Bones and joints. So that was my subspecialty, if you like. But I got interested in epidemiology, which is the study of risk factors in populations where you just look at thousands of people rather than one patient.

Really, I switched again to study because I got really interested in the idea that identical twins should be the same. They're clones that have lived all their lives together. All their genes are identical. What makes them different?

Counter to what everyone thought, identical twins often die at different times. They get different diseases. One gets depression. One's fine.

It's all these differences. So what that was my sort of conundrum. What makes identical twins different when they have the same life, they've lived the same lives? It was only through this sort of search to find this out that I looked at the gut microbes in twins and found they were different.

And that really scientifically took me onto this whole new path. From there, I made this sort of leap into nutrition to say, well, now we've discovered this whole new science. All this stuff we got wrong about nutrition suddenly makes sense. So now I would say I'm an epidemiologist who's really specializing in nutrition and gut health and trying to change the way people think about food.

That was a brilliant summary of your career and academic background. As a muggle like me, that's really new to many of these topics. What I understand is the study of epidemiology is the study of the like genetic root causes of disease, not just genetics. So it's any any root causes of disease.

So when people studying COVID were epidemiologists tracking a disease, trying to work out who's getting it, when it's coming back, how common it is. All these basic things in populations at a sort of big population level. Right. You've also written 800 articles, more than 800 articles on this subject matter.

In 2014, you set up the British Gut Microbiome Project and you've written five books on these subject matters. I mean, I've read two of them that I sat in front of me here. I'm really intrigued by the personal story as well, because writing these books and doing all the work you've done is a lot. It's a lot of work.

It requires a lot of drive. I mean, this particular book you said it took almost six years to finish. What is the personal drive behind that? What is driving you to pursue this subject matter?

You know, I just love getting into a new area, finding out that something that everyone's been quoting for decades is total BS. And it's based on some tiny study of nine people. It's like I'm a detective. And so I've always had this this quest to sort of be this obsessional detective, I think, going into these areas.

And at the same time, it's that's coincided with, you know, various events in my life as well that have probably pushed me in certain directions more than other, you know, that I wouldn't have gone otherwise. What were those events in your life? I guess, you know, I was a bit lazy student at school. That surprised some people.

People assume if you're a professor and you've made it, you're a swot at school. But I did the absolute minimum. So I scraped into medical school, scraped through the first few years of medical school. I spent one year proving that you didn't have to go to any lectures and could still pass, which was a lot of work.

Actually, at the end, I realized it's harder. Then, of course, age 21, my father died suddenly overnight with a heart attack. No warning at all. I was off on a skiing holiday with some friends.

And I think in retrospect, that that event changed me and perhaps gave me, you know, a bit more direction and drive than I would have had. I'm not quite sure, you know, how it would have turned out if he hadn't died. But to me, him dying at 57 suddenly like that made me think I need to, you know, make more of my life. I could die early, too.

This was something that I think spurred me on to do all this kind of stuff that I didn't need to do, but I felt perhaps more compulsion to do. And maybe also got me interested in this whole idea of genetics to say, well, you know, did he have rotten genes? Have I got the same genes? Am I going to die in my 50s?

So I think that looking back now, I think that's it's hard to be actually sure, but that seems a reasonable scenario. I read and I've heard from members of your team that that left you with a feeling, as you kind of said there, that you might also die young if it is a genetic thing. Definitely, yes. No, I always tell my kids, you know, this is this is it, you know, I'm only here.

I was sort of half joking, but saying, well, you know, my time's I've only got seven years to go now, you know, whatever it is. You're saying that to your kids? Yes. To try to prepare them?

I guess so. But it was my way of, you know, I did it in a jokey way. It wasn't like I was writing my will and saying, you know, the candlesticks are here and the everything else. But it was, yeah, I used to make light of it.

But, you know, underneath it, yes, I felt, well, you know, I could go early, so I need to get on with it, I think. And I was also at that time, process speed was sped up by another personal incident I had at that time, which was a mini stroke. Yes, we call it a mini stroke. It's a vascular occlusion.

But I couldn't work for three months. I couldn't read. And I got a bit depressed about that. So those three months where you can't read, I read that you were the quote.

I went from being a sporty, fitter than average middle aged man to a pill popping depressed stroke victim with high blood pressure. They said you were floored by this experience. And for three months, you couldn't work from having a pretty fast paced, frenetic life to being bedbound. And in those three months, you you're focused on the microbiome increases, right?

Yes, I was. I was just finishing up the very last bits of the previous book, Identically Different, which was about why twins are different. Right. And as an afterthought, I added one page about, well, actually, the microbiome could be the key to this.

What is the microbiome? It's the word we use for the community of gut microbes. These are microscopic bugs in our intestines. And it's a biome because it's like this jungle community.

It's a lots of different species altogether, thousands of them that coexist in our in our lower intestine, our colon. And they it's like we've discovered in the last 10 years a new organ in our bodies. If you put them all together, they weigh about the same as our brain. OK, so that's mind boggling, really, to think about all these bugs which individually are tiny, pulling together, they actually weigh several pounds.

So you can either think of them as a microbial garden. But increasingly, I'm shifting that towards thinking of them as an incredible pharmacy. So all of them are able to pump out chemicals all the time that are vital for our body. So thousands of different chemicals are pumped out every minute by these these gut microbes when they're fed the right foods.

And these chemicals are key for our immune system. Most of our immune system is actually in our gut. Most people don't know that. We think it's under our armpits or somewhere.

But actually, all the immune cells are actually talking all the time to our gut microbes through lost half of the good ones compared to if you go to hunter-gatherers or, you know, I spent some time with the Hadza tribe in Africa and, you know, they have twice the number of species that we have because they don't pop antibiotics, they don't have sterile foods, they have a very wide range of diverse plants, etc. So I think people think that, you know, they've got microbes, they're really only there to hurt them when they have a bad kebab or something. They don't think of all the positive benefits, they don't think that you need to build them up and that actually, you know, they're like a, the more you've got, the better it is. How do I build them up?

How do I become more like that tribe? You have to have a more diverse range of plants. So we did a study a few years ago with the British and American guts that showed that if you can get up to 30 different types of plants a week, you maximize your diversity of species in your gut. And that's that diversity that we want.

Remember, 30 plants, you look a bit shocked, but that's, it's a plant is a nut, a seed. It's not just kale. It's a herb, it's a spice. And things like coffee are a plant to me because it comes from a fermented bean.

So it's that diversity, it's having more fermented foods, it's having a range of colors, it's cutting out the ultra-processed chemicals as well, which all the groups in the population that have the best gut microbes, they don't eat ultra-processed foods, they don't have antibiotics, they don't have this modern Western lifestyle. You mentioned calories there as well, um, when you're talking about the microbiome. One of my friends is a prolific calorie counter and, you know, he eats a lot of Domino's pizzas. He listens to this podcast, he's gonna know exactly, he's gonna know that I'm atting him.

Um, he eats Domino's pizzas all the time, he eats like a real, you know, processed food diet, but then says to me, it's all about calorie counting. Now, with all due respect, friend, um, he's never managed to, but it's not necessarily worked for him in terms of the goal that he's set himself. So when I was reading about your view on calorie counting in your book Spoon Fed, it was, I screenshotted it this morning and sent it to him, and I said, you are a bullshitter. That's what I said in the message, and we had a good laugh about it this morning.

But what is your view on calorie counting and this idea that we can, you know, weight loss or being healthy is just about having a calorie deficit? It's complete nonsense. Thank you. I'll clip that and send it to him.

There's never been any long-term study showing that calorie counting is an effective way to lose weight and maintain weight loss after, you know, the first few weeks. So yes, very strict calorie counting. If you deprive yourself for a few weeks, you will lose some weight, but even if you're successful, your body's evolutionary mechanisms will make you hungrier and hungrier every week you go by where you're depriving yourself of energy. Your body will go into sort of shutdown mode, your metabolism slows down, so you're not expending those calories.

And inevitably, I'd say more than 95% of people will go back to their baseline and many go above it. There's a rebound back if they're doing this, this style of calorie restriction. Now, calorie counting is a part of that. So people try and say, okay, I'm not going on a dramatic diet, but I'm going to just try and reduce by 10% my calories in the day, which in the old theory was supposed to make you lose weight.

Well, it's virtually impossible even professionals to count calories and because they're not very accurate for a start, everything on the packet, you have to weigh everything. And in restaurants now, you're supposed to have these calorie counts. They're plus or minus about 30% because portion size makes such a huge difference to it. It's, and it's been shown in the U.S.

to be a worthless exercise anyway. So you can't count them going in. You can't really count your metabolism going out either. We're all incredibly different.

You know, your friend's probably been told 2,500 calories is what he's allowed. Well, that's an average, but it doesn't mean it's related to him. My average is much lower. I mean, I tested it.

So everyone is an individual. And this is another thing we need to move away from this one size fits all guidelines. But I think more importantly is that the whole calorie counting assumption means that it doesn't matter what form that calorie is. It has the same effect on your body.

Therefore, whether you're cutting out fat calories or carb calories or, you know, low calorie sodas or whatever it is, it's going to be fine. But we now know that's not true. And there's several science experiments which now absolutely nail that. One was in America where they gave people identical meals for two weeks in a sort of enclosed semi-prison.

And one was homemade and one was ultra-processed. Both identical calories, macros the same. The group with the ultra-processed foods over-ate by about 200 calories every day. They kept going back to the buffet for more.

Okay, so yes, the same calories, but the effect on the body meant they were hungrier. Why is that? We don't know for sure. It could be that those chemicals in the ultra-processed foods affect the gut microbes and they then send signals to the brain saying, eat more.

This isn't a natural, you know, this is a really weird chemical and it's doing something weird to me. I'm producing something weird in exchange. It could be they get absorbed much quicker. So you get a big sugar rush and the nutrients get into your body in a way faster than they should do in nature.

And so your brain doesn't have time to say, I'm full. It normally takes 20 minutes or so to get that fullness. Or, you know, so it could be the matrix of the food. It could be the chemicals in the food.

It could be its effect on the gut microbes. But it also could be things like your sugar spikes. So in the Zoe predict studies where basically we've given now 50,000 people in the US and the UK the same foods at the same time, same time of day. Everyone's got these muffins.

We show that people, one in four people who have these muffins and wearing a, we wear glucose monitors, which tells you for two weeks what's happening with your glucose. One in four people get a real sugar dip three hours later. So this is where your rise in sugar, which is normal. And then as it comes down, it goes below baseline, but only in one in four people.

And when that happens, those people end up overeating the next meal. And during the day, they feel more tired, more hungry. That's this, the sort of 11 o'clock slump, if you like, if you've had a carby breakfast, some people feel that others don't. And what's really interesting is they say one in four people eating identical muffin of identical calories will then overeat by this, you know, another 10% that day.

So you can see how that just blows the calorie idea out that the calories in equals calories out. Everything's the same. And the third thing is that ultra processed food says it has the calories that's equal to the whole foods, but often they don't account for the fact that it's ground up. It's highly refined.

And so if you take like almonds or something like this, you might use ground almonds and you compare ground almonds to whole almonds. There's perhaps 30% less available calories in the whole almonds than there is in the other ones. So the whole thing is a complete nonsense. And it's there because the food industry wants you to focus on the calorie, the fat content, sugar.

So you don't have to think about the quality of the food. And it's something that they can control very easily, get their profits higher, keep adding stuff to the product that's synthetic. When we know that a lot of things they're adding are harmful for our gut microbes. So the artificial sweeteners are harmful.

The glues, they stick the foods together. The emulsifiers, some people react quite a lot to those and they cause problems. So the whole thing is like this giant camouflage. And that's really one thing I'm, you know, probably my number one bugbear is to get people to see the light, stop obsessing about calories and start thinking about food much more as quality and what it does to your body.

Quality food. What is quality food in your definition of the phrase? It's the opposite of ultra processed food, which is whole food, which is made with from the original ingredients of plants, mainly plant-based, but it's not exclusively that contains all the nutrients that those plants produce without it being stripped away or boiled up or highly pressurized, deformed. And so they have to add in back those nutrients.

So, you know, it's things in their pure form. So it's, it's nuts, it's seeds, it's, it's grains that haven't been ground up super finely. It's all the amazing plants and fruits and vegetables that we've got. They, they're healthy foods, but you know, it's, it's not straightforward.

Yes, I've got this list of 10 superfoods. It's understand that many foods that, you know, are healthy for us, most of them are in their, in their original form. Berries, nuts, virtually every vegetable is healthy for us if it's in that original form. It's only because we've, we had to learn to preserve things.

We had to do trickery to make, you know, margarines and things with chemistry that we've moved away from that. But, you know, I completely changed two of my meals completely. So I'd gone from having muesli with low-fat milk and an orange juice and a cup of tea, because I started doing these tests with Zoe, I found out that gave me a massive sugar spike, and it was a terrible way to start the day and I got these dips at 11 o'clock, to a high full-fat yogurt, nuts, seeds, a few berries, and I never have orange juice. That's a really unhealthy drink for everybody.

And I have lots of black coffee, which I now know is good for me. So that's totally different. I changed my lunch for at least 10, 15 years when I was in the hospital. I was having hospital lunch, which used to be in the canteen, then it was Marks & Spencer's, got the healthy-looking sandwich with brown bread, sweetcorn, and tuna, and a smoothie, a little bottle.

And that gave me a massive sugar spike. And I wouldn't have known that. And I was told that should have been a healthy thing to eat. So, you know, there's general rules, but also there are specific rules.

And this whole idea of individuality is coming in. So it could be that you might be fine on that. Don't know. I was very annoyed because when I started, we were starting doing this testing for Zoe, I had all these spare kits and I gave my wife one as well.

And we sit down and she's a French-Belgian and loves croissants. And so we'd have a croissant each. Mine would shoot up. She had no change at all in her sugar, which was really annoying.

So, but it also brings home the fact that, you know, everyone loves simplistic rules, but you can only get so far with them. You have to start experimenting yourself and see what works for you and not just take everything for granted. And that's really the, that's the whole essence of really, you know, setting up this personalized nutrition research and Zoe and everything else. But on top of this general advice about changing the whole idea of food, I think, because I think they do go hand in hand, that if you realize all these individual differences, you realize it's not as simple as you've been told.

It's not that fats are evil. It's not that calories are bad. You know, it's much more nuanced. You mentioned breakfast there.

I heard that you do some intermittent fasting. Intermittent fasting. I think I pronounced that correctly. Intermittent fasting.

Yes. We'll just use AI to swap that for my voice. What is it? It's intermittent.

Let's just call it fasting. Just for people at home that can't say it. Fasting has become a really popular thing over the last three or four years. A lot of my friends talk about it.

Again, it's almost feels like it's going into fad territory again. But what is the, what are the facts around fasting intermittently? Okay. It's, I guess it's been quite a hot topic for about 10 years now, but it's intermittent fasting is the umbrella term for all kinds of different fasting.

And you might remember the 5-2 style of intermittent fasting was quite big about 10 years ago. And there were also these extended fasts often used in America, people doing two or three day fasts and detoxifying, that sort of stuff. So you've got to realize that you have to specify what time, what we're talking about. But I think the most interesting type of fasting now is what's called time-restricted eating.

Time-restricted eating. I can see that. TRE. Okay.

So the idea is you don't change what you eat, you just change how you eat. And you change your eating window. So most people in the UK and the US, they'll be eating for 14 or 16 hours a day. That's me.

Right. Lots of snacks and extending late night. And what time-restricted eating is, you're trying to reduce that to something like 10 hours on average. Okay.

It varies. There are some more extreme ones, some milder ones, but that seems to be about the sweet spot that most people can manage. 10 hours, which means you start eating at 11 and you finish at 9, for example. Or you might want to go from 8 in the morning until 6 at night.

Or 7. I can't do my maths. Now, there's actually science behind this now. So there's plenty of studies showing that not only in mice and rats, this helps their metabolism, their energy management, but there's some evidence it helps with weight loss to a small extent, but it improves your inflammation levels and a lot of people report energy and mood improvements.

We've just done a big study with the Zoe Health Study, which is the free app where we had 130,000 people sign up to do this trial, if you like, where they would do this for two weeks. And amazingly, most people managed it. And we did see improvements in mood and energy just in that two-week period. And actually hunger went down, weirdly.

But a lot of this we found is people were actually snacking less. So we won't tell them to do less. You can do whatever you like in that time, but people just paying more attention and not grabbing something to eat just before they went to bed. Now, the science behind it is really interesting because your body needs time to recover.

So your cells, we're programmed on the circadian rhythm that is very much in line with the sun from, you know, when we were all in East Africa and it was everything was quite programmed so that our body is in the state of work during the day. We eat, do all our stuff. And then at night it recovers. As the stress hormones go down, then you repair stuff comes out.

So it cleans up all the muck in our cells. But we now know that it's the same happening in our guts. So if you rest your gut for 14 hours, you give time for all the other microbes to come out and act as a repair team, like a cleaning force that hoover up all the mess you've left behind. They clean up nicely your gut wall.

And so it's not leaky, you get rid of inflammation. And this change, giving them this break really seems to have these great benefits. So I'm, I was a real skeptic about this and I did lots of fasting and things for experimenting with the books. But I think the last two years I've really been convinced that this is something that does work and is right for some people.

But importantly, it's not right for everybody. And there is an individuality. You may be a snacker that finds it very hard to go long periods of time without eating. Okay.

I do know. We've got several people at Zoe who say, oh, this is terrible. But for me, you know, I suddenly realized when I wake up in the morning, I'm not starving. It's not the first thing I think in my head.

And it's very easy to wait till 11 o'clock to have something to eat. And it's not a big deprivation. It's something you could carry on the whole of your life, which I think is what we're into here. So I think there's a lot to be said for this, but I think people need to personalize it.

Again, you know, people love a single, single black and white solution to all their problems. But I'd say to everyone, try it. You may want to do a sort of American style, eating really early and finishing early. You might be that kind of person who's a sort of morning person, or you might be someone that prefers the social life of eating in the evening and skipping the morning.

It's going to be take quite a lot of discipline for me to stop having chocolate at 2am. So could you just summarize again, time-restricted eating? The key benefits of it are my microbiome will be healthier, gives my microbiome more time to clean up, which will have an impact potentially on weight loss and overall energy levels, etc, etc. Mood.

OK, cool. That's enough for me. I think that's a convincing enough reason. And I imagine there's also an impact on sleep there because, you know, me having chocolate at 2am is probably not going to give, help me have quality sleep at night.

Absolutely. Yes. No, I think there is a link. We're studying that.

We don't have any results from that trial, but we are logging sleep quality as well. But personally, I've, when I've started to do it, I do sleep better. I did start to get some reflux as well. So a lot of people suffer from heartburn.

Right. And that's again, because you're eating and drinking alcohol quite late. They're not leaving enough time to go to bed. That causes sort of stress on your body when it's supposed to be relaxing.

So I think, yeah, everyone give that a, you know, give that a try and it could be right for you. And it just makes you think also just thinking about more what you're eating, you know, to say, okay, let's give my body a rest. Just like you would if you had an exercise regime or whatever. It's just thinking about eating in a different way other than just fuel.

What about vitamins? You know, I've got all these vitamins by my bedside, not by my bedside, by my bathroom sink in my bedroom. Because, you know, I went to the market and the lady there told me that all these vitamins are important. And then I don't know, I've seen an ad on Facebook or something and I ended up buying more vitamins.

And I've got like a collector of vitamins. You're not alone. I think 50% of the British population have a regular vitamin or supplement every day. And it's a massive industry.

I read chapter five of your book. So I'm a bit rude about vitamins in there. Please, please So you could say you really improved your diet because it sounds like you had a pretty shitty diet before that, right? So you know what I mean?

So anything could have been an improvement if someone says if you're eating real foods, right? So yeah, sounds like the keto, you weren't having keto out of a bottle or a plastic. No, no, no, I was having meals. Yeah, I was proper home cooked meals rather than takeaways.

Exactly. So you're making the shift from perhaps, you know, the average UK diet, which is high in refined carbs, which is, you know, probably had a fair bit of ultra processed foods in there as well, to this other diet. So I would expect you to feel better. To be a keto diet, you've got to get to about 70% fat, right?

Which is really, really hard for anyone to sustain. It's virtually impossible. That's why I said for the last few months, I'm no longer on the keto diet. So, you know, you've gone, so you are probably done a mild keto diet, right, that didn't put you into ketosis, but got you off these high refined carbs.

Yeah. So, but going back to the basic question, keto diets do seem to work for people with diabetes or overweight as a way of getting off their medications and sort of kickstarting them into a better health pattern. And there are some people I think it can work for. I think as a sustainable diet, I don't think it makes any sense.

I don't think many people can still be on it a year later if it's a true ketogenic diet, because no studies have really shown that people can sustain eating that level of fat and protein and virtually no carbs. That's all I ate for about eight weeks. Yeah, but you were eating plants as well. So I'd have like some plants.

It wasn't just steak, was it? I mean, at one point it felt like that. There was some plants in there, sort of like lettuce and broccolis and stuff like that. But I was Googling everything to check if it was keto friendly before I put it in my mouth.

So, yeah. So I think what's interesting is if you, you went from that to a more mixed, healthy, gut friendly diet, you know, which includes fermented foods, small amounts of breads, grains, et cetera. I think you'd still find the same benefits because you're shifting from ultra, you know, because I'd suspect if you did the Zoe test, for example, you would have a quite a big reaction to sugars and your fat control would be quite good. So it sounds like you tolerate quite large amounts of fat without too much problem.

Whereas the sugars would spike like me. You get a reaction, you get hunger, you get, you know, these feelings of tiredness, et cetera. So just by upping your fat levels, lowering your refined carb levels, you might have produced the same without doing that extreme idea. Because my problem with the keto diets is ultimately it's restrictive.

You're reducing the number of foods you're thinking about. You're ultimately then harming your gut microbes long term because you're not giving them the variety of different plants if you're not careful. And that happens to a lot of people. They go down any of these slightly fatty diets and they end up with a much more restrictive, you know, intakes than they would have done, which long term will cause some problems for their immune health and long term health.

So that's why I'm generally against these extreme diets of any kind other than if you are a seriously ill diabetic and you're overweight for three months, it could be a really good way to get you off your meds. Interesting. Yeah, because I'm trying to I'm trying to find now. So I went from the keto diet to the New York diet.

Basically, we went to New York for two weeks and I just I really fucked up. But now I'm back. I'm trying to find the nice middle ground, the sustainable middle ground. That word sustainability in my diet and also my fitness has been key to me because if I can't sustain it, there's no point doing it because you end up yo-yoing afterwards.

So I went from the keto diet, as I said, to the New York diet. And now I'm back in the UK. So go on the gut-friendly diet, which is please do tell the gut friendly diet. Just it's, you know, 30 different plants a week, lots of fermented foods.

That's your yogurts, your kefirs, your kombucha. And if you like kimchi, kraut, miso, koji, Japanese food, eating the rainbow. So you've got plenty of colors on your plate. Everything's got because that means that you've got plants there that have got these defense chemicals.

And we haven't talked about these, but these are the polyphenols that are in plants that give them their bitter taste, but also the bright colors that you get in berries and you get in bright colored lettuce and cabbages and they are rocket fuel for your gut microbes. So the more you've got of those, the healthier your gut, the more you dampen down inflammation. So really important to as much diversity, lots of color and lots of high polyphenol foods, things you wouldn't have thought are healthy. So dark chocolate.

I know you like dark chocolate. Well, I'm not sure is it milk chocolate you have. Well, you need to change to dark chocolate. My girlfriend says that she's obsessed with dark chocolate.

Well, and she always tells me. Take a lead. Slowly, slowly wean yourself off the milk and get on to real chocolate. OK, which actually tastes of something really good rather than sugar.

Isn't white chocolate the worst? Yes. Do you know how I knew that? That's the only thing I know about food.

I went into a chocolate making class and at the start of the class, the instructor says, pour the sugar into these big tubes. And she said, pour the sugar into the tube. So I'd like pour a bit in. She was like, no, no, no, no.

Fill that tube with 60 percent sugar. I was like, what? She was like, fill the tube with. I was like, why?

That's white chocolate. It's 60 percent sugar. So I pour this this sugar into this tube and it fills it 60 percent. And then I put this little like oily liquid in and she was mix it.

And she was like, that's white chocolate. 60 percent sugar. There's people right now that are sat there eating it and realise that they're giving themselves early onset diabetes. So dark chocolate is a good example.

Coffee, we already mentioned. Do you like coffee? I do. Well, I don't.

For me, coffee is more of a utility. I use it before I have these conversations so I don't fall asleep because I'm very, you know, I've never been good. You might have a boring guest. Well, sometimes, but it's more so just to try and keep my mind sharp and to keep focused.

But I read chapter 13 of your book about coffee and I've always been a bit of a coffee skeptic because I tend to have a belief that everything in life comes at a cost. And no one I've sat here with has ever been able to tell me the cost of an artificial boost in my focus, attention, energy. I feel like nothing's free in life, you know, so what is the cost of coffee? Well, I think there's a variability.

Some people, there is a big cost. They get the shakes. They can't sleep. And it has other neurotoxic effects if you have too much.

So I think it's all about dose. And this is, it is a drug that if you get the dose right, it's very beneficial for you. If you get it wrong or you've got some genetic problem, you can't process it right. It's a problem.

But some of the benefits I was talking about are also there in decaffeinated coffee. So it also has these because again, it's a great example of how we always think of coffee as caffeine. And yet if you do these epidemiology studies and these big population ones, people who are having regular decaf coffee also have similar heart benefits. So it's other things in this fermented bean that are helping us.

And I think this is just, you know, it's a great lesson moving away from our reductionism. We always like to think of, you know, one food is one vitamin or one chemical. And that's an easy way to think about it. We can't comprehend they've got a thousand different ingredients.

So decaf coffee, but yeah, well, you've got green tea is also pretty good. You know, there's many other fermented foods, but the polyphenols are really good and important to realise. And in the book Food for Life, I go into exactly that. It's a practical guide to when you go into the supermarket and you go to the aisle.

So, gosh, I'm in the vegetable aisle. Do I get my usual iceberg lettuce that 90% of us do because it lasts for two weeks or, you know, longer than our prime ministers. Or do we go for slightly more expensive, loose leaf rosololo with purple leaves that has a thousand times more polyphenols. So you really shop on colour.

Yes, now I do. I had no idea about this until doing it. But also, the fact it's loose leafed means that those plants have had to survive in more difficult conditions to fight off predators and wind and everything else. So they're tougher.

That's why herbs and spices are also tough because they're the growing tips of the plant. That's where you get the good bits. And so it's a rethinking all this idea about what's good about food when you start thinking about your gut and the sugars that it releases, etc. So for you, yeah, I mean, if I think as a general rule, if everybody to keep their gut microbes happy We've got a fitness group amongst some of my friends.

There's about 10 of us in it, and we've been tracking how often we work out and how frequently we work out and the workouts that we do. And one of the things I have to say is pretty much no one in the group has lost any weight. We've been doing this for a year. And that kind of bucks what you would think.

So the only time that I lost weight was actually when I went on the keto diet. I went from 14 stone 8 to 13 stone 8 in roughly in several weeks. But exercise and exercising for almost religiously for the last two and a half years doesn't really seem to impact my weight at all in a, you know, in a way that the fitness experts might tell me on Instagram. What's your stance on the role that exercise plays in weight loss?

There's very little role in weight loss. All the studies, long-term studies show it doesn't help weight loss. And it's been grossly exaggerated as an easy fix for our obesity problem. Exercise doesn't help weight loss.

No. All the studies show that the only caveat to that is if you have changed your diet, improved your diet, and you've lost some weight, maintaining some exercise does help prevent it going back up again. But as on its own, if you don't change your diet, it's of no use. And that's well known now by all the obesity experts and all the studies.

Does sugar make us fat? Is that the culprit? Is that one of the main things that should be eating to... No, again, that's reductionism, you know.

But the reason exercise doesn't work, it's important to realize this, is because we all know this, that, you know, you go for a walk, you build up hunger before a meal. It's what your parents told you, you know. And anything about exercise is after it, your body slows down, your metabolism slows down, and it tries to regain the energy that you've lost. That's just our evolution.

And so that's why it's great for your health. I mean, I exercise. Fantastic for your mood. It's great for your heart, anti-cancer, all kinds of things.

We should all do it. But absolutely not if your goal is weight loss. You have to do something about changing your diet. And I think that's the big, a huge myth, particularly perpetuated by gyms and fitness apps and everything else.

And it is complete nonsense. I read that when you looked at studies over 30 years and you looked at how many studies had been done on the relationship of exercise and weight versus things like sugar and weight, there was 12 more, 12 times more studies done on the relationship of exercise and weight versus sugar and weight. And why is that? Why is there less research done on the latter?

I think that's the influence of governments and the food companies and the drink companies. So a lot of the exercise research done in the last 20 years was sponsored by large corporations who wanted to make this link between exercise and weight loss so that they could continue to sell sugary ultra-processed foods and drinks and just say, it's the childhood obesity because we don't have playgrounds and we don't encourage this. And that's why the Cokes and Pepsis are always there at the Olympic, sponsoring Olympic events and associating themselves with sport. And they gave hundreds of millions to various physiology departments, sports departments, nutrition departments to do research in this area.

Basically, it was really hard to get anyone to do research into how sugary drinks make you gain weight or cause problems because the amount of money for nutrition has been abysmally poor from governments. And that's why, you know, only the first ever study of ultra-processed food in a controlled trial was only about three years ago. And it's been around for, you know, 30, 40 years. So such is the power of that lobby that it doesn't necessarily distort the research in an sort of either way, but they point it to make sure that the researchers are working in an area that they want people to work in and distracting them, keeping away from talking about sugars or even artificial sweeteners, which in my view are nearly as bad because they're sort of hidden and deflecting us from the idea that, yes, giving kids sugary drinks or even artificial sweet drinks is going to be bad for them and cause obesity.

Wait, so I've been, I've cut out sugary drinks about a year ago. I still have the same brands, but I have the no sugar version. Oh dear. Oh shit, what do you mean, oh dear?

Well, the summary of the trial shows that if you take young adults and kids and they were, say, on two cans of, you know, full sugar sodas and you change them to the diet version, there's no real difference in weight or metabolic changes in their blood. You will go to the dentist less, so you don't get as many fillings but, and yet, you should be gaining 300 calories, right, if you're doing two cans a day. So it doesn't work out as it should do, and that's because of the extra, these chemicals are not inert. So the sweeteners in kids, they change their brains to give them, they want more sweetness in their food.

Okay, so it could reflect your wish for your late night milk chocolate, who knows? And it makes it very difficult to train kids to have more bitter foods or sour foods if they've got these artificial sweeteners in their diet all the time. But they've now shown that all these sweeteners actually affect your gut microbes. So even stevia, you know, these so-called healthy ones, have an effect on your gut microbes and they're not inert.

So, you know, the saccharin and sucralose also cause spikes in your blood sugar. And I did it, you know, I have a trace. They're not supposed to, but they actually do things they're not supposed to. So we know very little about these products and my view is that they are harmful, probably not as bad as having the sugar, but they are absolutely not a health drink and we should be encouraging people to have, you know, teas and kombuchas and more bitter tasting, interesting flavors and foods than just this ultra sweet chemical concoctions.

Is this, this sugar conglomerate that have been funding much of the research that points towards some of the things you're talking about there, that's also the conglomerate that wants us to believe the calories in, calories out approach because if I just view all foods as kind of equal and on this sort of calorie number, then I can drink some of the sugary fizzy drinks and some of the processed foods. As long as I keep it within that sort of calorie deficit, I'll be fine. And so are they, is that sugar conglomerate, is the processed food conglomerate for the calorie model? Absolutely.

They need that, right? Absolutely. It's vital, you know, zero calories or one calorie, you know, on the can, that's what you see. And you know, you're fooling people into thinking this is a healthy drink and oh, you know, if I used to have full Coca-Cola or Pepsi and now I'm having the diet version, I'm getting 300 calories less a day, I should lose weight.

It's exactly what they've been doing and they're also desperate to show that artificial sweeteners are really healthy and they come down on anyone who tries to say that they could be in any way dangerous. And yet they're not obliged to test them. So none of the chemicals added really go through rigorous testing on how they affect our gut microbes. And this is, you know, their testing methods haven't changed in 50 years.

The gut microbiome, the microbiome as an organ, one of the things you talked about earlier was the impact it has on mood. And, you know, this podcast was started as kind of a business podcast. We have a lot of people that are interested in, you know, being more productive, being more successful, reaching for their goals. How significant and how pertinent is the microbiome on my performance as an entrepreneur, as a business person?

What do I need to know about the relationship as it relates to my mood, my performance, my mind? Well, we know more about mood than anything else. And so we do know that depression and anxiety is intricately linked to the quality of your gut microbes. We know this from mouse studies where they've transplanted poo from anxious mice into sterile mice and those new mice then become anxious and depressed.

Really? So it's a transmissible condition. And if you go back to me telling you that one of the chemicals that our microbes produce is serotonin, okay, some sort of cuddle, you know, love, friendly, warm chemical that affects our brain, that, you know, is the key to dopamine and everything else that goes on in our head. So the levels of that are really important for us having the right neurochemical balance in our head that stops us getting very depressed or very anxious.

So we know that you can transmit it between animals. So when they say you take the poo out of one mouse, they put it inside its gut, inside its stomach to give it the same microbiome makeup inside its stomach. Yes. And then that mouse will become depressed and anxious.

Yes. So a lot of the science behind microbiome is based on large scale human studies where you've just got cross-sectional data. Well, this is associated with this, but you don't know if it's cause or effect. And so there's this whole other group that's been going on of projects for 30 years where they have these sterile mice who have no microbes.

And you create in a lab these other microbes that would make them anxious or they're genetically anxious. You look at their microbes and you take their microbes and you put them into the sterile mice and you can change their mood and their attention span and everything else. So that shows that these have a direct effect rather than just Countries like China and Japan at the bottom of the pack. What's your overall view on these disorders, depression, mental health, anxiety?

Do you think it stems predominantly from the microbiome? Is that your perspective now, from what you've learned? No, I think they're multifactorial. So I think we can't just blame the gut microbiome because you do get these conditions in people who are otherwise healthy.

Genetics plays a role. Going back to my old career, a lot of evidence of strong genetics in things like depression and anxiety. Do you think it stems predominantly from the microbiome? Is that your perspective now, from what you've learned?

No, I think they're multifactorial. So I think we can't just blame the gut microbiome because you do get these conditions in people who are otherwise healthy. Genetics plays a role. Going back to my old career, a lot of evidence of strong genetics in things like depression and anxiety.

But you can have a tendency to it, but you need to be triggered into it. You don't need some environmental event. And it could be that once your gut microbes get in such a bad, your gut health is such a poor state, your diet is so bad, that triggers this and you just lack those chemicals that tip you over into it. So that's why I think if you link these epidemics, which we're going through at the moment, whether it's dementia, depression, obesity, diabetes, what do they all link for?

Increasing amounts of ultra-processed foods in our diet. We're the number one country in Europe for this. Rates are still going up. Kids have over 70% of their food as ultra-processed now.

Horrendous. Adults, it's nearly between 15 and 60% of our meals. So I think that's affecting the gut microbes, probably just tips this threshold in people who are susceptible. So it could be that I think that threshold is going to vary genetically.

Some people are very resilient. Some people are actually quite susceptible. And that's my view of it, which isn't popular because it's, again, I make things more complicated than people like. But, you know, I think as a scientist, I think most of these diseases are built up of a different number of risks.

But unlike your genetics, you know, your gut health is something you can do something about. And that's what you're doing with Zoe. Exactly. That's the whole idea behind Zoe is to empower people to change their health by individualizing what they eat that suits their own metabolism.

What is Zoe, if someone's hasn't heard of Zoe before? Zoe is a personalized nutrition company that I founded nearly six years ago with two of my co-founders who came to one of my talks. I was talking about the diet myth and the microbiome, and they came up to me and said, We think what you're doing is really exciting. We'd love to talk about getting a company together to personalize this.

And I do get people asking me to do startup companies. And I said, I'm not really interested unless we can spend several million on doing research first. You know, I'm not interested in the usual lifestyle company based on marketing. And I thought I'd never see them again.

But they came back two weeks later, said, Yes, we've got several million. We're up and running. So I was stuck and I couldn't say no. And basically, we got together this massive study called the PREDICT study, which looked at 1000 people, mainly twins, gave them these identical meals, gave them these really fancy tech, glucose monitors, measuring blood spots with fat, looking at their microbes, logging foods, seeing how they got on for two weeks and use that data as algorithms to then predict how people respond to any food.

And then we developed a home test and launched that initially in the US and in the last year, the UK. And we've now got 50,000 people have been in this identical home test, which is now a program that then once you've got your scores personalized to you, you can look up any food and it gives you a score from zero to 100 on what that how that food is for you based on your sugar, your glucose, blood sugar profile, your fat profile and your microbiome. So it's pushing everyone to have less sugar peaks, less fat peaks and better gut health. And so it's changed.

You know, so in a way, that's my muesli would give me a terrible score. My orange juice would, you know, a score of zero. But it's also made subtle changes. So, you know, I used to eat bananas and now they score badly.

So now I have pears instead or apples. Little minor shifts, often pushing people. And then you and you have a virtual nutritionist who helps you plan your menus to get overall scores that are pushing you more and more in this healthy direction. So you start to understand what's best for your body and in a sustainable way.

And we don't talk about calories. It's like a taboo word. And we're not after crash dieting or anything else. It's like improving yourself from the inside out.

So you and most people get improved, dramatic improvements in their energy levels, which we hadn't even thought about was the reason. But people started telling us, I feel much better because maybe we're cutting out all these fat and sugar peaks that until the technology came along, no one knew about that were causing these problems. So it's going super well. We've got still a quarter of a million people waiting for the product in the UK on the waiting list.

And what's really nice is because we've got this commercial arm, it allows us to do these other Zoe Health Study, which is a free app, which now is moving that towards lifestyle like this, these fasting aids and things like this. We've got a neat podcast, the Zoe nutrition podcast, which is doing the word out about our science plus logs and things. So, you know, it's part of a whole package of things that we're doing to sort of educate people differently. And as I said, make people think about food in a very different way.

And I think it's super exciting because we're, you know, we've just raised some more money. We've done some crowdfunding as well, which has gone amazingly well. I saw it this morning. Yeah, it's a big valuation for a company.

Yes, it is. 200 million. That's a big number. It is.

And it's but, you know, I think we've just got people's attention exactly the right time. I agree. And the technology has just been exactly right. So often it's about timing.

Yeah, I agree. I mean, as I said to you before we started recording, I've had two of my guests come here and tell me about Zoe individually. So I think it was Davina McCall and Gabby Logan who both mentioned it. And then I had this email in my inbox from a friend of mine who connects me to George.

And then I started reading about some of the work that you'd done and some of your videos. And that's why I was compelled to reach out and have you on this podcast. But the idea of personalized health kind of debunks the longstanding narrative and myth that there's this one perfect diet for all of us. There's this one set of foods that we should all be eating to be healthy.

And this personalized approach makes a lot more sense. So I think that's the kind of the moment in time that you've arrived perfectly in from a Zoe perspective is this awakening to the perspective that personalized individual diets are the way forward. Yeah. And, of course, COVID didn't, you know, COVID was an amazing time for apps and people wanting to take control when they feel they had no control.

So I think the idea that you give people an app and they suddenly are empowered to do things is a very new idea, particularly in the UK. People said no one over 60 is ever going to do that. They told us it's going to fail. And it was an incredible success because if you give people that interaction, that feeling that they are talking to someone and they're getting information back and it's a two-way process, it's a completely different idea to the old way of communicating with people.

So I think it is a super exciting time for science. You know, we've just scratched the surface of what we can do with this personalization because once we get to a million people, you know, the levels of detail we can provide back about whether you should be eating in the mornings and the evening, you know, how hungry does this food make you feel? You know, how do you stop you individually stop getting those sugar dips? How, in what combination of foods should you have, you know, how do you react to protein?

What do you do to best sleep well? All these things which people want to know are going to be possible once we get these huge numbers. This is all quite, you know, it's all, I'm going to have this conversation with you, then I'm going to turn on the TV or go on the internet or go on Instagram. And all of the influencers there are going to be telling me a bunch of stuff, a bunch of fatty diets because they've all got their own incentives and their own ways of making money.

If there was like one principle I could take away from all of your work, which I know is almost an impossible task, but if there was one thing just to focus on as I try and navigate the bombardment of social media and advertising posts that I'm going to be on the receiving end of as I leave this conversation, what would that kind of guiding principle be for me not to forget? Pick changes that are going to last for life, not as a quick fix. I think that's what we're after. And that's what we want to try and instill is this sustainable, healthy way of eating.

So that means not feeling like I'm not depriving myself. No. Okay. I think absolutely the philosophy we have at Zoe is that nothing is off the table.

There's no, nothing's banned. White chocolate. I think it's part of that grieving process, probably, that having lost someone, you always feel somehow responsible. You should have done something before.

I think that's part of it. And many people have recurrent dreams also about because my father, you know, I never saw him. I was just told he's dead, came back from holiday. That was it.

Go to the funeral. And it was a quite unreal series of events for me. And so for years, I used to have these dreams. You know, he'd been in South America and suddenly appeared again.

Oh, so I had to disappear and I'd come back. So that was an interesting idea going on my brain that in some ways he wasn't really dead and you know, I'd get a chance to talk to him again. So it must have been, you know, a key part in those subconscious bits of my brain. That communication goes both ways, though, doesn't it?

Because they have to also be... Yeah, in retrospect, you know, he was very much a, you know, a 1960s dad that, you know, who wasn't really supposed to deal with children or anything else. He went to work and stayed in his study and because he wasn't sporty, he never did anything with me. So absolutely.

Yeah. It's... But as I think you've talked about before on this podcast, you know, children have a very different perception of that relationship. They feel it's, It's their fault in a way.

But yeah, he was not a... by modern stands, he wouldn't have been seen as a great dad. Tim, thank you. What a wonderful conversation.

Really, really appreciate your time and thank you for coming in and sharing your wisdom with me. Absolute pleasure.