Doctor Tim Spector: The Shocking New Truth About Weight Loss, Calories & Diets (Transcript)

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.

Understanding Epidemiology

STEVEN BARTLETT: That was a brilliant summary of your career and academic background as a muggle like me. That’s really, you know, 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.

TIM SPECTOR: Not just genetic. So any…

STEVEN BARTLETT: Any cause of disease. Right.

TIM SPECTOR: So the people studying Covid were all epidemiologists tracking a disease, trying to work out who’s getting it, when it’s coming back, how common it is.

STEVEN BARTLETT: Right.

TIM SPECTOR: All these basic things in populations at a big population level.

Personal Drive and Motivation

STEVEN BARTLETT: Right, got you. 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 are 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?

TIM SPECTOR: 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 was based on some tiny study of nine people. It’s like I’m a detective. And so I’ve always had 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.

STEVEN BARTLETT: What were those events in your life?

Life-Changing Events

TIM SPECTOR: I guess, you know, I was a pretty lazy student at school. That might surprise some people. We always assume if you’re a professor and you’ve made it, you were a swat 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 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 was 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 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 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, 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 absolutely sure, but that seems a reasonable scenario.

STEVEN BARTLETT: I’ve read, and I’ve heard from members of your team that that left you with a feeling, as you’ve kind of said there, that you might also die young. If it is a genetic thing, definitely yes.

TIM SPECTOR: No, I was always telling my kids, you know, this is it, you know, many – how many? I was sort of half joking but saying, well, you know, my time’s, you know, I’ve only got seven years to go now, you know, whatever it is.

STEVEN BARTLETT: You were saying that to your kids.

TIM SPECTOR: Yes, you know that.

STEVEN BARTLETT: To try and prepare them.

TIM SPECTOR: I guess so. But it was my way of, you know, I did it 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, price speed was sped up by another personal incident I had at that time.

STEVEN BARTLETT: Which was a mini stroke.

The Mini Stroke and Its Impact

TIM SPECTOR: 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.

STEVEN BARTLETT: 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, your focus on the microbiome increases. Right?

TIM SPECTOR: Yes. I was just finishing up the very last bits of the previous book. Identically different. Which is about why twins were different.

STEVEN BARTLETT: Right.

TIM SPECTOR: And as a sort of afterthought, I had acted one page about. Well, actually the microbiome could be the key to this.

STEVEN BARTLETT: What is the microbiome?

Understanding the Microbiome

TIM SPECTOR: It’s the word we use, 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 lots of different species altogether. Thousands of them that coexist 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. Okay. So that’s mind boggling really to think about all these bugs which individually are tiny. Putting 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 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 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 these chemicals. And our immune system obviously is crucial for our whole body and fighting aging and cancer, COVID infections, allergies, all these kind of things.

So then you’ve also got – the microbes can produce chemicals that affect the brain and will make the difference between you being happy or sad or. We know that they’re vital in depression, important for regulating how much you eat, your appetite, when you feel full. They also provide key vitamins for you, all the B vitamins and many other components, neurochemicals like serotonin, that’s key for happiness, and how antidepressants work are all produced by your gut microbes.

So we’re slowly learning that these guys are absolutely crucial to how our body responds to anything coming into it, whether it’s painkillers, whether it’s antidepressants, whether it’s chemicals in the form of food. And this is why, you know, I want people to think about food very differently than we have done in the past.

The idea, the old idea that food is just calories, macros, you know, with its fats and carbs and proteins, those four things, you know, that’s 100 years old mentality. But key to it is this core of our gut health, which we’ve ignored totally.

And this was this big aha moment for me after research for 10 years. Why would identical twins be different? What could it be? And it turns out their gut microbes are different. That’s the only thing I’ve ever found in 30 years that’s really different about identical twins. And that explains why one gets cancer the other one doesn’t, why one gets an autoimmune disease, or one’s depressed and one’s happy. So for me, that the twins were perfect. Obvious way to show that, how important these microbes are for all of us.

Common Myths About Gut Health

STEVEN BARTLETT: What are some of the biggest myths you encountered as you started researching the microbiome that most people currently believe that I probably sat here, now believe about how to keep my gut healthy? What are some of those key myths? Because I know you like myth busting.

TIM SPECTOR: Well, I think most people believe that probiotics in yogurt get killed by your stomach acid. So they don’t work because everything gets killed off. That’s a common one, I hear. But they don’t. No, some get killed, but you’re ingesting billions, so always enough get through to have an effect. And we know that probiotics do work, although the best probiotics are in food rather than in capsules and there’s plenty of fermented foods which is the same.

I think most people know very little about microbes. They think that most of them are harmful. So, oh, you know, they cultured this microbe or they found a parasite. 50,000 people have now looked at their gut microbes in the US and the UK. In the UK, 24% have a parasite and that parasite is actually beneficial. It’s called Blastocystis and it’s associated with good health, being thinner, having less internal fat, lower blood pressure.

And, you know, in the past we’re trying to kill it off and actually the reason we’re in this state is we’ve killed off a lot of our good bugs. So I think people need to realize that most of the bugs in our system are trying to help us and we’ve actually 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, their gut microbes are really only there to hurt them when they have a bad kebab or something. They don’t think of all the positive benefits, that 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.

Building Up Your Gut Microbes

STEVEN BARTLETT: How do I build them up? How do I become more like that tribe?

TIM SPECTOR: You have to have a more diverse range of plants. So we did a study a few years ago with British and American guts that showed that if you can get up to 30 different types of plant 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.

The Problem with Calorie Counting

STEVEN BARTLETT: You mentioned calories there as well when you were 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 going to know exactly, he’s going to know that I’m talking about him. 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, he’s never managed to… I shouldn’t say that, but it’s not necessarily worked for him in terms of the goal that he set himself. So when I was reading about your view on calories in your book Spoon Fed, it was, I screenshotted it this morning and sent it to him. And I sent, I said, “You are a bullshitter.” That’s what I said. 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.

TIM SPECTOR: It’s complete nonsense.

STEVEN BARTLETT: Thank you. I’ll clip that and send it to him.

TIM SPECTOR: There’s never been any long term study showing that calorie counting is an effective way to lose weight and maintain weight loss after 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 hungry 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 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 for 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, we’re supposed to have these calorie counts. They’re plus or minus about 30% because portion size makes such a huge difference to it that it’s been shown in the US 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 probably 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 relates to him. My average is much lower when 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.

Why All Calories Are Not Equal

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 in 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 overate by about 200 calories every day. They kept coming back to the buffet for more. Okay, so yes, the same calories, but the effect on the body meant they were hungrier.

STEVEN BARTLETT: Why is that?

TIM SPECTOR: 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 natural. 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 signal. 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 spike.

Individual Responses to Food

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 we wear glucose monitors, which tells you for two weeks what’s happening in your glucose. One in four people get a real sugar dip three hours later.

So this is where you 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 their next meal and during the day they feel more tired, more hungry. That’s this 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 that so one in four people eating an identical muffin of identical calories will then overeat by 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 almonds or something like this, they 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 one.

The Food Industry’s Calorie Deception

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, 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.

What Is Quality Food?

STEVEN BARTLETT: Quality food. What is quality food in your definition of the phrase?

TIM SPECTOR: It’s the opposite of ultra processed food, which is whole food which is made 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 back those nutrients.

So you know, it’s things in their pure form. So it’s nuts, it’s seeds, 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’re healthy foods but you know, it’s not straightforward. Yes, I’ve got this list of 10 superfoods. It’s understanding that many foods that you know are healthy for us, most of them are 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 had to learn to preserve things. We had to do trickery to make, you know, margarines and things that, with chemistry that we’ve moved away from that. But you know, going back, olive oil for example, is a great example of something that’s vilified often because it had lots of fats in it. And you know, certainly I was told the Mediterranean, they have olive oil on everything. “It’s horrible. It’s all fatty.”

Turns out that’s perfect. You know, it comes from the olive, the good stuff. Extra virgin olive oil has very little done to it. And that is a good healthy quality food. But it can be refined. You can take that and you can keep refining it. You can take corn on a cob as an example. And then you’ve got, I don’t know, tortilla chips or something down the other end, which bears or corn flakes, which bears no resemblance to the original. And there are more versions on the spectrum.

Navigating the Supermarket

STEVEN BARTLETT: God, it’s so confusing, you know, because what you said to me is, you know, based on research and studies. But then when I go to a supermarket labeling even I just thinking then cornflakes, I think I grew up thinking cornflakes were healthy because it says corn in the title. You know what I mean?

And when you’re trying to navigate. I was just thinking, if I’m going down an aisle now, hearing what you’ve just said, that quality food is food that is not ultra processed and kind of resembles its original form. 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? I mean, I can go to the vegetable aisle and I can say, “Okay, that looks like a cabbage. It looks like no one’s messed with that. There’s been no study done on that. It hasn’t been through a laboratory.” But how do I, if I’m in an aisle tomorrow, how do I know what food is good and what is not?

TIM SPECTOR: Well, you said the first thing. If it’s not in a package, you’re pretty sure it’s good. Okay, so if it’s concealed in some package that’s got, you know, happy children and signals of vitamins in it, that should be a warning sign. You know, the more they have to advertise the food and say what its additives are and everything, the more you should be wary about it.

The number of ingredients is another pretty good sign. So once you get over 10, particularly if there’s lots you’ve never heard of, you wouldn’t find in your kitchen, you should also be wary that that is ultra processed food. Anything that says “low calorie” that says means they’ve had to add in lots of artificial sweeteners or protein extracts or something else is also a big danger sign. “Low in fat” means they’ve replaced the natural fat with something else that’s cheaper. And these are all warning signs.

Personal Food Transformation

And you take breakfast cereals. I used to eat lots of breakfast cereals. I was brought up on them. Highly sugary stuff. And then I thought I was being healthy when I moved to mueslis and posh stuff. But actually when you still, you know, that appearance of healthiness, it’s still got lots of additives in it, it’s still got lots of sugar in it.

And those cereal packets have added vitamins in it, but they’re often in a very poor form. I did the experiment once where I took some cornflakes or Special K, I can’t remember that said had added iron. And if you mix it up, you can put a magnet on it. You can get off the iron filings. They’re so cheap that they’re just added to tick a box saying it has iron, but they don’t get into your body or do anything.

So anything that’s got these things added “with this in it,” “low in this” is a sign that they’re obscuring the quality of the product. So it’s, you know, but it’s a lot of brainwashing. You know, we’ve been brainwashed for years and decades in this and you know, I was as well as a doctor, you know, I should know better. And yet I’ve completely changed my two of my meals completely.

So I’ve gone from having muesli with low fat milk and an orange juice and a cup of tea because I did, you know, I started doing these tests for Zoe. I found out that gave me a massive sugar spike and was a terrible way to start the day. And I got these, you know, dips at 11 o’clock to a high full fat yogurt, nuts, seeds, a few berries and never have orange juice. That’s on my… 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 got in the hospital, I was having a hospital lunch which used to be in the canteen then it was the Marks and Spencer’s. Got a healthy looking sandwich with brown bread, sweet corn and tuna and a smoothie in 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, I 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 French, Belgian and loves croissants. And so we’d have croissant each, mine would shoot up. She had no change at all in her sugar, which was really annoying.

STEVEN BARTLETT: Yeah.

The Importance of Personalized Nutrition

TIM SPECTOR: So, but it also brings home the fact that 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 essence of setting up this personalized nutrition research and Zoe and everything else.

On top of this general advice about changing our idea of food, I think they do go hand in hand that if you realize there are 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. It’s much more nuanced.

Time Restricted Eating and Intermittent Fasting

STEVEN BARTLETT: You mentioned breakfast there. I heard that you do some intermittent fasting. Intermittent fasting, I think I pronounced that correctly.

TIM SPECTOR: Intermittent fasting.

STEVEN BARTLETT: Yes. We’ll just use AI to swap that for my voice. What is it? 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 almost feels like it’s going into fad territory again. But what are the facts around fasting intermittently?

TIM SPECTOR: Okay, I guess it’s been quite hot topic about 10 years now. But intermittent fasting is an 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. Oh gosh, yeah, that sort of stuff. So you’ve got to realize you have to specify what we’re talking about. But I think the most interesting type of fasting now is what’s called time restricted eating.

STEVEN BARTLETT: Time restricted eating, I can say that TRE.

TIM SPECTOR: 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 US they’ll be eating for 14 or 16 hours a day. Right. Lots of snacks and extending late night and what time restrict eating is. We’re trying to reduce that to something like 10 hours on average. Okay, varies. There are some more extreme ones, some milder ones, but that sees throughout 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.

There’s actually science behind this now. So there’s plenty of studies showing that not only in mice and rats, this helps them, 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 were 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 when we were all in East Africa and it was. Everything was quite programmed so that our body is in this 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 your repair stuff comes out. So cleans up all the muck in ourselves.

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, get rid of inflammation. And this change giving them a break really seems to have these great benefits.

So I was a real skeptic about this and I did lots of fasting and things for experimenting with 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.

I do know we’ve got several people at Zoe who say, oh, this is terrible. But for me, 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 very easy to wait till 11 o’clock to have something to eat. And it’s not a big deprivation. That’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. 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.

STEVEN BARTLETT: It’s going to 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. Mood. Okay, 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 help me have quality sleep at night.

TIM SPECTOR: 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 thought 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 try and it could be right for you and it just makes you think also just thinking about more what you’re eating, to say okay, let’s give my body a rest. Just like you would if you’re doing an exercise regime, whatever. It’s just thinking about eating in a different way other than just fuel.

The Truth About Vitamins and Supplements

STEVEN BARTLETT: 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 some market and the lady there told me that all these vitamins are important. And then I don’t know, I might have seen an ad on Facebook or something and I ended up buying more vitamins and I’m like a collector of vitamins.

TIM SPECTOR: We’re not alone. I think 50% of the British population have a regular vitamin or supplement every day and it’s massive industry.

STEVEN BARTLETT: I read chapter five of your book.

TIM SPECTOR: So I’m a bit rude about vitamins in there. Please, please. So I know it’s the thing that upsets people. Most people say. I believe everything else you say, but I don’t believe your chapter on vitamins. And again, it’s a bit like a religion, popping a pill and hoping that it’s doing some good.

All the evidence shows that when you do a randomized controlled trial, these vitamins don’t work unless you’ve got some really weird disease or deficiency or for some reason you can’t eat a normal diet. But it’s a last resort for people who have terrible diets. If you have a decent varied diet with plenty of plants in it, you don’t need vitamins at all.

And I used to take them and I don’t take any now, except the occasional B12 because I’ve always been low in B12 and I have hardly any meat. But apart from B12, all the evidence points to these things being a complete waste of money.

STEVEN BARTLETT: You’re telling me all those vitamins I’ve swallowed over the last 10 years have been a result of me being duped by the vitamin industry and have no material impact on my health?

TIM SPECTOR: Yes. Well, they might have had some harmful effects, like people taking calcium and things like this shown if you take regular calcium tablets, more likely to get heart disease.

STEVEN BARTLETT: You’re joking. I’ve literally got a tub of calcium tablets by my kitchen sink as we speak.

TIM SPECTOR: Yeah, well, there’s calcium in nearly every plant and things that we normally break down, absorb in small amounts regularly. You take something like a calcium supplement, you might be taking half a gram of it. Our body isn’t designed to break down that huge slab of chemical and so it doesn’t get distributed well. And studies show that it gets deposited in your arteries and can harden them up.

So there’s no evidence that calcium helps people, doesn’t help broken bones, it doesn’t help osteoporosis, all the things that we were told it did do. So all the evidence was out there and you’ve got all these companies pushing it. So many of these things can be counterproductive.

But my main worry about them is if people think they can pop a pill, they don’t have to think about proper food.

STEVEN BARTLETT: Yeah.

TIM SPECTOR: And therefore everything can comes in a bottle or a pill. They can go, just have a junk food diet and be healthy. And that’s so wrong, because diet, I think, is the most, as I said, the most important food choice we make for our health. And to take stuff that doesn’t work, that could be counterproductive and sometimes harmful is a daft delusion.

STEVEN BARTLETT: I have been under a daft delusion. I’ve got so many supplements upstairs.

TIM SPECTOR: Could have a placebo effect. You might feel better because you’ve taken them.

STEVEN BARTLETT: You know, I feel like a healthy person because I take them. I don’t know whether I am a healthy person, but I feel like one. When I do it, I do it and it’s really uncomfortable because I’m taking. Sometimes I’m taking like eight different pills, like calcium and potassium and whatever else. And when I’m doing it, even though it’s hard to swallow them and it tastes rancid, I feel like I’m doing future Steve a favor.

TIM SPECTOR: Yeah, well, there you go.

STEVEN BARTLETT: But clearly I have.

TIM SPECTOR: Get someone to make you some dummy ones. So there’s got nothing harmful in it and you can a lot cheaper.

The Ketogenic Diet Experience

STEVEN BARTLETT: I’ll give that a shot. What about sugar? So I was keto for the last, roughly the last two months. I tried the diet because I had a lot of good things about the ketogenic diet as it relates to inflammation. And I have to be honest, I lost about a stone in weight fairly quickly. First time I’ve really seen a huge dip in my weight.

But also not just that. The gut issues that I’d had seemed to go. So I’d almost lived for the last couple of years. Specifically, like after the age of 25, for some reason, suddenly foods that I thought had gluten in them, like white breads and pastas and even like soy sauce and things like that were making me live in this permanent state of, like, being bloated. And I’d go to the toilet and I didn’t feel great. It was kind of this pain throughout the day, a couple of hours after eating one of those foods.

And then I tried the ketogenic diet. So I cut out pretty much all of those things. Like I didn’t have any bread, most of the sort of processed bad carb. I don’t even know what I’m talking about here, so correct me, but I cut out what I thought were the bad carbs that were having a bad reaction to me. And then I cut out a lot of sugar, like refined sugars, basically cut it completely out. And I ate meat, vegetables, berries and things like that.

Felt fantastic. Lost a stone in weight. Very, very, very lean body fat. Dropped completely. Slept well, high energy. What’s your view on the ketogenic diet?

The Keto Diet Experience and Sustainability

TIM SPECTOR: Well, your story is, I mean, you can take two ways. One, you could say you really improved your diet because you had. It sounds like you had a pretty shitty diet before that. Right, so. So, you know, I mean, so anything could have been an improvement if someone says, if you’re eating real foods. Right, so, yeah, it sounds like the keto. You weren’t having keto out of a bottle or a plastic.

STEVEN BARTLETT: I was having meals. Yeah. Prepare them for me.

TIM SPECTOR: Proper home cooked meals rather than takeaways and.

STEVEN BARTLETT: Exactly.

TIM SPECTOR: 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, yeah, which is really, really hard for anyone to, to sustain. It’s virtually impossible.

STEVEN BARTLETT: That’s why I said for the last two months, I’m no longer on the keto diet.

TIM SPECTOR: So, you know, you’ve, you’ve gone, you’re. So you have probably done a mild keto diet, right, that didn’t put you into ketosis but got you off these high refined carbs.

STEVEN BARTLETT: Yeah.

TIM SPECTOR: So, but going back to the basic question, keto diets do seem to work for people with diabetes who are overweight as a way of getting them 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.

STEVEN BARTLETT: That’s all I ate for about eight weeks.

TIM SPECTOR: Yeah, but you were eating plants as.

STEVEN BARTLETT: Well, so I’d have like some plants.

TIM SPECTOR: Wasn’t just steak, was it?

STEVEN BARTLETT: It was, I mean, at one point it felt like that it was. There was some plants in there, there was 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.

TIM SPECTOR: So, yeah, so I think what 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, etc. I think you’d still find the same benefits because you’re shifting from ultra, you know, because I would suspect that if you did the Zoe test, for example, you would have 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, etc. 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, 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 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 seriously ill, diabetic and you’re overweight for three months, it could be a really good way to get you off your meds.

Finding Sustainable Middle Ground

STEVEN BARTLETT: Interesting. Yeah, because 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.

TIM SPECTOR: So go on the gut friendly diet which is.

STEVEN BARTLETT: Please detail. The gut friendly diet just it’s, you.

The Gut-Friendly Diet Approach

TIM SPECTOR: Know, 30 different plants a week, lots of fermented foods. That’s your yogurts, your kefirs, your kombuchas, 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 they’ve, 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, as well as 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, doctor. Well, I’m not sure. Is it milk chocolate? You have it?

STEVEN BARTLETT: Yeah, it’s milk chocolate.

TIM SPECTOR: Well, you need to change to dark chocolate.

STEVEN BARTLETT: My girlfriend says that she’s obsessed, obsessed with dark chocolate.

TIM SPECTOR: Well, and she always tells me, take her. Lead it slowly, slowly wean yourself off the milk and get onto real chocolate. Okay. Which actually tastes of something really good rather than sugar.

STEVEN BARTLETT: Isn’t white chocolate the worst?

TIM SPECTOR: Yes.

The White Chocolate Revelation

STEVEN BARTLETT: Do you know how I know that? That’s the only thing I know about food. I went and did a chocolate making class, and at the start of the class, the instructor says, “Pour the sugar in.” So we had these big tubes and she said, “Pour the sugar into the tube.” So I’d like, poured a bit in. She was like, “No, no, no, no. Fill that tube with 60% sugar.” I was like, “What?” She was like, “Fill the tube with.” I was like, “Why?” She goes, “That’s white chocolate. It’s 60% sugar.”

So I pour this sugar into this tube and it fills it 60%. And then I put this little, like oily liquid in. And she was.

TIM SPECTOR: Mix it.

STEVEN BARTLETT: And she said, “That’s white chocolate, 60% sugar. There’s people right now that are sat there eating it. They’d realize that they’re giving themselves early onset diabetes.”

Coffee: The Complex Stimulant

TIM SPECTOR: So dark chocolate’s a good example. Coffee we already mentioned and if. Do you like coffee?

STEVEN BARTLETT: I do.

TIM SPECTOR: Well, I don’t.

STEVEN BARTLETT: 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.

TIM SPECTOR: You might have a boring guest.

STEVEN BARTLETT: Well, sometimes, but it’s more so just to try and keep my mind sharp and to keep focus. 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 with 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 for free in life, you know? So what is the cost of coffee.

TIM SPECTOR: 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. So I think it’s all about dose. And this is. It is a drug that if you get the dose right, is 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 real. 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, you know, 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 polyphenols are really good and important to realize. 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 a slightly more expensive loose leaf rossolo with purple leaves that has a thousand times more polyphenols.

Shopping by Color and Plant Defense

STEVEN BARTLETT: So you really shop on color.

TIM SPECTOR: Yes, now I do. I had no idea about this until doing it. But. But also the fact it’s loose leaved means that those. 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 all the good bits.

And so it’s a rethinking all this idea about what’s good about food in this, when you start thinking about your gut and, you know, the sugars that it releases etc. So for you? Yeah, I mean if, I think as a general rule, if everybody ate to keep their gut microbes happy, they’d be on a pretty healthy diet even before you get into personalization now, chapter 13.

Coffee Can Save Your Life

STEVEN BARTLETT: Of your book, we talked about coffee there is called “Coffee Can Save Your Life.” You mean that quite literally, don’t you?

TIM SPECTOR: Yes. As an epidemiologist, if you drink three cups of coffee a day, you are less likely to die 10 years later.

STEVEN BARTLETT: Jesus Christ. But there’s also a link between coffee, depression and suicide, right?

TIM SPECTOR: Well, there are lots of links because.

STEVEN BARTLETT: I was reading that in studies people were less suicidal if they’d been drinking coffee.

TIM SPECTOR: I think that, I’m sure there is a study on that. In general, what I do when I look at these is I don’t take any one study on its own. I’ll try to get look at all the literature and say how many studies there are in that and is there a confirmatory one that would make it real or not. So I’ve tried not to over claim. Yeah, because if you look at, you know, you look at the Daily Mail or you know, the general press in the UK, they will pick up on any one story and say coffee gives you cancer, coffee does this, coffee gives you dementia next year. You know, it saves your life, it does this so you can switch.

But what I think people need to do is, you know, especially after Covid, is be much more sort of selective about how they see a study. It’s epidemiology that it has to have confirmatory data. So I think, yeah, coffee, we know it improves sports performance by 1%. Right. So for most people that doesn’t really matter. Right. You know, 1%. Am I going to run faster on my treadmill at the gym by 1%? No.

But it, it does give you a little bit of focus and for most people it’s, it, you know, it’s a good drug that’s found in food and I like coffee because also it helps. It’s allowed in a fast, so time restricted eating. You allow black coffee and black tea and it, because it doesn’t cause a sugar spike or anything else, but it’s, you have to cut out the sugar.

The Truth About Gluten Intolerance

STEVEN BARTLETT: I feel like more and more people are becoming gluten intolerant. I consider myself one of them. I am a self diagnosed gluten intolerant. I read chapter 16 of your book and you think most of that is made up?

TIM SPECTOR: Yes, most people who think they’re gluten intolerant aren’t when you test them. That’s the fact. It doesn’t mean that everyone’s making it up. Some of those will be real. But I think gluten got this bad rap about 10 years ago and we know that yes, 1% of the population really do have a gluten problem. It’s called Celiac disease and they’ll be vomiting and have terrible diarrhea with the smallest bit of gluten.

Then there’s a whole other group of people that believe they have gluten intolerance, of which studies show about three quarters when they’re tested with gluten are fine in a blind, blinded way. If someone slipped you a biscuit or something, or pasta is often the way to trick people. And I think many people have probably a more general irritable bowel syndrome that are blaming gluten because they’re taking that one protein that they know about from foods that have thousands of them and saying, “This is the problem” – again, this reductionism.

And then they cut everything out. But they might be cutting out things that were like the sandwich, for example, that was causing glucose spikes. So they might feel better when they cut that out. And they then say, “Okay, I’ve cut out bread, therefore I’m not getting sugar spikes and tiredness. That must have been the gluten.” But actually it was nothing to do with that. It’s just cheap bread that has nothing to do with it.

So I think often people are taking gluten as an excuse, and sometimes they do feel better when they cut out those foods because they’re eating less processed foods as a result of it. Not always, but it’s something else in the bread or the pasta that they were eating too much or they were eating too fast or these things that I think are important.

So I would urge everyone to look again at where there is gluten or it is something else about their food habits before that was bad and reevaluate it and build up your plant diversity and your gut microbes instead. Because the worry is that all these people on gluten, most of them have a rather restrictive diet. They get very worried about new foods. And that’s the worst scenario because you end up on a vicious circle where you get more and more nervous. So you have a smaller and smaller group of foods you’re happy with, your microbes get diminished, and you have much less flexibility to deal with any new food that hits you.

Exercise and Weight Loss: The Uncomfortable Truth

STEVEN BARTLETT: One of the things I have to say is pretty much no one in our fitness 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 several weeks. But exercise and exercising religiously for the last two and a half years doesn’t really seem to impact my weight at all in the way that the fitness experts might tell me on Instagram. What’s your stance on the role that exercise plays in weight loss?

TIM SPECTOR: Has 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.

STEVEN BARTLETT: Exercise doesn’t help weight loss?

TIM SPECTOR: 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 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.

STEVEN BARTLETT: Does sugar make us fat? Is that the culprit? Is that one of the main things that’s contributing to…

TIM SPECTOR: No, again, that’s reductionism. But the reason exercise doesn’t work, it’s important to realize this is because we all know this, that you go for a walk, build up hunger before a meal. That’s what your parents told you. And everything 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 you’re not going to… it’s great for your health. Exercise is 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 a huge myth particularly perpetuated by gyms and fitness apps and everything else. And it is complete nonsense.

The Corporate Influence on Exercise Research

STEVEN BARTLETT: 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 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?

TIM SPECTOR: 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 childhood obesity is because we don’t have playgrounds and we don’t encourage this.

And that’s why the Cokes and the Pepsis are always there 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 the first ever study of ultra processed food in a controlled trial was only about three years ago and it’s been around for 30, 40 years.

Such is the power of that lobby that doesn’t necessarily distort the research in an evil 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 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.

The Problem with Artificial Sweeteners

STEVEN BARTLETT: Wait, so I’ve cut out sugary drinks about a year ago. I still have the same brands, but I have the no sugar version.

TIM SPECTOR: Oh dear.

STEVEN BARTLETT: What do you mean oh dear?

TIM SPECTOR: Well, all the summary of the trials shows that if you take young adults and kids, and they would say on two cans of 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 you should be gaining 300 calories, right? If you were doing two cans a day. So it doesn’t work out as it should do.

And that’s because these chemicals are not inert. So the sweeteners in kids, they change their brains to give them, they want more sweetness in their food. 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, these so called healthy ones have an effect on your gut microbes and they’re not inert. So we know that saccharin and sucralose also cause spikes in your blood sugar. When I did it, they said 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 teas and kombuchas and more bitter tasting, interesting flavors and foods than just this ultra sweet chemical concoctions.

The Calorie Model Conspiracy

STEVEN BARTLETT: It’s 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?

TIM SPECTOR: Absolutely.

STEVEN BARTLETT: They need that, right?

TIM SPECTOR: They absolutely. It’s vital, “zero calories” or “one calorie” on the can. That’s what you see. And you’re fooling people into thinking this is a healthy drink. And “Oh, I used to have full Coke or Pepsi and now 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 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 their testing mechanisms haven’t changed in 50 years.

The Microbiome and Business Performance

STEVEN BARTLETT: The gut microbiome, the microbiome as an organ. One of the things you talked about earlier was the impact it has on mood. And this podcast was started as kind of a business podcast. We have a lot of people that are interested in 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?

The Gut-Brain Connection and Mental Health

TIM SPECTOR: Well, we know more about mood than anything else. And so we do know that depression 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, so we saw the 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.

STEVEN BARTLETT: So when they say they 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.

TIM SPECTOR: Yes.

STEVEN BARTLETT: And then that mouse will become depressed and anxious.

TIM SPECTOR: Yes. So a lot of the science behind microbiome is based on large scale human studies where you’ve just got cross sectional data or 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 off 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 about that. So that shows that these have a direct effect rather than just being secondary.

And that links to the human data that shows if you take a groups of depressed or anxious people, virtually all of them will have deranged microbiomes and be producing abnormal chemicals. And there have been now some recent studies showing that compared to traditional antidepressant medication, probiotics do as well. In many of these studies, if you give a course of probiotic medication.

But even more impressive is if you give them a Mediterranean gut friendly diet, you get actually better results with more remission than you do with antidepressant medication. So it’s one of the best examples of how, you know, feeding your gut can actually improve your mood.

And it’s particularly important because we’re seeing, you know, an epidemic of anxiety and depression. That’s partly because of not having many good gut microbes to start with. Lots of junk food diets which make it worse. And then of course, once you go into that cycle, once you’re depressed, you’re not thinking about food, the last thing you want to go at is, you know, “oh, I’ve got to go and get my kimchi today.” You know, you just. What? It’s just fuel.

So once you understand that, you realize if you want to help someone with depression, you know, the first thing is not to put them straight onto an antidepressant, which in many cases doesn’t work because of this individuality as we’re talking about, which probably again related to the microbes because they break down the tablet into its active chemicals. But it’s to make sure they’ve actually got gut friendly diet. And so this is a really exciting area of research.

The Microbiome and ADHD Connection

STEVEN BARTLETT: You mentioned attention, the impact that the microbes can have on attention. That’s really interesting to me because ADHD has become a very widely discussed topic. Do you think there’s a link between ADHD and the microbiome?

TIM SPECTOR: Highly likely, yes. I mean, there’s less data in it than there is in depression anxiety. The studies are smaller, but those that I’ve seen all show again, an abnormality in the gut microbiome of ADHD kids. And there’ve been a few studies showing that you can reverse it with poo transplants, which is another area that was quite big a few years ago. It’s not showing the same potential as it did, but certainly affecting attention and mood with gut microbes is definitely on the cards.

These studies need to be bigger, but there’s certainly preliminary evidence that what’s true for depression anxiety is also true for this whole spectrum of other conditions also, you know, that have been linked in the past to diet and, you know, over sugar and E numbers and all these kind of things. So we’ve sort of known vaguely there’s an association, but I think people haven’t really pinpointed the gut microbiome, which I think they should.

And so absolutely sure that if you improve the diet of many of these kids with ADHD, you would improve their symptoms. And I know there are some ongoing trials at the moment.

The Rise of Mental Health Issues and Antidepressants

STEVEN BARTLETT: It’s really been startling over the last couple of years how mental health has really taken centre stage in conversations, even conversations on this podcast. Most of them, we discuss mental health issues and things like anxiety and depression. And as we look around the world, the stats around people that are being prescribed antidepressant pills like they called SSRIs, I believe is rising. And I think it’s doubled over the last decade or so with the US kind of leading the way and then other countries like China and Japan at the bottom of the pack.

What’s your overall view on these, 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?

TIM SPECTOR: 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, you know, otherwise healthy. Genetics plays a role. You know, I’m going back to my old career. A lot of evidence of strong genetics in things like depression, anxiety.

But you can have the tendency to it, but you need to be triggered into it. You 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, you know, depression, obesity, diabetes, what are they all linked? For increasing amounts of ultra processed foods in our diet, you know, we’re the number one country in Europe for this. Rates are still going up. Kids have over 70% of their food is ultra processed now horrendous adults, it’s nearly, you know, between 50 and 60% of our meals.

So I think that effect on 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.

STEVEN BARTLETT: And that’s what you’re doing with Zoe.

TIM SPECTOR: 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?

STEVEN BARTLETT: What is Zoe, if someone hasn’t heard of Zoe before?

TIM SPECTOR: Zoe is a personalized nutrition company that I founded nearly six years ago with two 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, you know, 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. 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. Then I couldn’t say no.

And basically we got together this massive study called the Predict study, which looked at 1,000 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 met about 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 doing this identical home test, which is now a program that they. Then, once you’ve got your scores personalized to you, you can look up any food and it gives you a score from 0 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 scored badly. So now I have pears instead, or apples. Little minor shifts, often pushing people.

And then 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 just start to understand how 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.

And most people get dramatic improvements in their energy levels which we hadn’t even thought about as 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. We have the Zoe Health study, which is a free app, which now we’re 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 getting the word out about our science, plus blogs 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.

STEVEN BARTLETT: I saw it this morning. Yeah, big valuation for a company.

TIM SPECTOR: Yes, it is. And you know, I think 200 million.

STEVEN BARTLETT: That’s a big number.

TIM SPECTOR: It is. And it. But you know, I think we’ve just got people’s attention exactly the right time.

STEVEN BARTLETT: I agree.

TIM SPECTOR: And the technology has just been exactly right. So often it’s about timing.

The Future of Personalized Nutrition

STEVEN BARTLETT: Yeah, I agree. I mean, I’ve had, as I said to you before we start 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 connected me to George. And then I started reading about some of the work that you’d done in source 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 long standing 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.

The Power of Personalized Health Apps

TIM SPECTOR: 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 ever 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 and we’ve just scratched the surface of what we can do with this personalization because once we get to a million people, the level of detail we can provide back about whether you should be eating in the mornings and the evening. How hungry does this food make you feel? How do you stop, you individually stop getting those sugar dips, how, what combination of foods should you have? You know, how do you react to protein or the, you know, 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.

One Guiding Principle for Healthy Living

STEVEN BARTLETT: This is all quite, you know, it’s all we turn on the. 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 influences there are going to be telling me a bunch of stuff, a bunch of fad 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 to do. 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?

TIM SPECTOR: 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.

STEVEN BARTLETT: So that means not feeling like I’m not depriving myself and.

TIM SPECTOR: No.

STEVEN BARTLETT: Okay.

Nothing Is Off the Table

TIM SPECTOR: I think absolutely the philosophy we have at Zoe is that nothing is off the table. There’s nothing that’s banned. White chocolate, even white chocolate, you can be the milky bar kid. You know, you can have it, but realize that, you know, it’s that rare treat, okay. And the more you just. And so it doesn’t break everything and you have to start again.

It’s about making sure that the rest of your week is full of good foods that give you a high score that can make up for it. So we all going to, you know, the Christmas season, everyone goes crazy and overeats and stuff. As long as you know you’ve got this long term plan that your gut is healthy and you’re working and you’re overall these, you’re not going to get these peaks over time for years. That’s the goal.

So absolutely. It’s about enjoying food, realizing that it’s incredibly important social event. It’s why the Mediterranean countries probably do so much better because it’s so much part of family life and social life, even in the elderly, whether it’s with a glass of wine, it’s just taking more time, enjoying the novelty of foods and increasing our range of foods.

So it’s really broadening it. So I really want everyone to love food again and not have all these hang ups about “I can’t have that, I can’t have this.” If you’ve got enough plants on your plate, face it, you know, you can eat anything.

Tim Spector’s Books and Resources

STEVEN BARTLETT: Tim, thank you. Feel like that’s a good place to end and I’m really going to go upstairs and reconsider that vitamin stack that I have and also throw out all those zero calorie sugar free drinks that I thought were good for me. You give me a lot to think about and I’m incredibly honored to have met you at this time in my life because as I said, it’s very relevant to me, but also to have been given the chance to read your books.

You’ve got so many amazing books, five of them in total. I believe you’re working on a new one. My favorite was these two. So the “Spoon Fed” book and also your most recent book, which is “Food for Life,” which is basically like a glossary of food. Is that an accurate statement? It goes through all the key main foods and talks about the role they play in our health.

TIM SPECTOR: Yes. I mean it’s been called a food bible A to Z, but it’s a practical guide to pretty much all the common foods so you can get what the latest science is telling you about them all from a ethical, health and environmental perspective.

A Personal Reflection on Loss

STEVEN BARTLETT: We have a closing tradition on this podcast where the last guest asks a question for the next guest, not knowing who they’re asking it for. So the question that’s been left for you is you seem nervous.

TIM SPECTOR: Yeah, I’m very nervous.

STEVEN BARTLETT: Why do people get. People always seem to get nervous when I ask this question, but my questions.

TIM SPECTOR: Ask me any science question. I don’t mind.

STEVEN BARTLETT: Well, it’s, you know, the question that’s been left for you is if you could say one thing to a family member you’ve lost, who would it be? What would you say and why?

TIM SPECTOR: Well, it’s got to be to my dad, I guess that’s. And I’d probably say “I’m really sad we never got to talk properly. And I think you’d be proud of me now” and. Because, as I’ve explained, he died when I was 21. It’s just the time you’re sort of coming out of studentship. You’re becoming more mature at the time you could start to talk to your parents, but you don’t. So I feel that’s my missing part of my life, if you like, that I never got to discuss anything meaningful with my father.

STEVEN BARTLETT: Why was that? I have that problem too now. Have that problem where I struggle to talk to my father.

TIM SPECTOR: I don’t know. I think in hindsight it’s a much easier thing to say, I should have done this. And I think it could be that it’s built into us that we have a very different relationship with our fathers that makes it hard to actually talk to them at the same level or not feel some sort of competition or critique.

So I think you’re absolutely right that if I was sat down here with my father, it would be quite different to wishing I had done all those years ago. And 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, he just. I was just told he’s dead, came back from holiday, that was it. Go to the funeral. And it was a unreal series of events for me. And so for years, I used to have these dreams. He’d, you know, he’d been in South America and suddenly appeared again. “Oh. So I had to disappear and I’ve 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.

STEVEN BARTLETT: That communication goes both ways though, doesn’t it? Because they have to also be.

TIM SPECTOR: Yeah. In retrospect, he, you know, he was very much a, you know, a 1960s dad, you know, who wasn’t really supposed to deal with children or anything else. His, 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 their fault in a way.

STEVEN BARTLETT: Yeah.

TIM SPECTOR: But yeah, he, he was not a. By modern standards, he wouldn’t been seen as a great dad.

STEVEN BARTLETT: Tim, thank you. What a wonderful conversation. Really, really appreciate your time and thank you for coming and sharing your wisdom with me.

TIM SPECTOR: Absolute pleasure.

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