ZOE Science & Nutrition - 5 foods I got wrong - Tim Spector

Episode Date: October 20, 2022

Where were you in 2015? President Obama was in the White House, The UK was a member of the European Union, and you couldn’t escape Bruno Mars's global smash: Uptown Funk. More importantly, 2015 marked the release of Tim Spector’s first book: The Diet Myth. If you think the world has felt different since 2015, wait until you hear about the advances in nutritional science. Since then, Tim has had a chance to rethink his position on dietary staples like bread, milk, ultra-processed foods and more.  He’s put everything he’s learnt into his new book Food for Life: The New Science of Eating Well.  In this episode, Tim speaks with Jonathan about what he got right, where he went wrong, and what the future holds for the world of nutrition.  Tim Spector is a co-founder at ZOE and one of the world's top 100 most cited scientists. Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:00 - Intro 00:10 - Topic introduction 02:33 - Quickfire questions 03:19 - Has Tim changed his opinion on anything while writing his new book? 03:55 - Tim’s new book: Food for Life 05:41 - Today’s topic: 5 foods Tim got wrong 06:55 - #1: Bread 10:16 - What has Tim’s opinion changed about bread? 12:23 - #2: Personalization 15:15 - How has Tim’s breakfast changed? 22:05 - #3: Milk 25:04 - Skim milk vs whole milk 27:48 - What kind of milk does Tim have? 29:43 - #4: Mushrooms 32:37 - #5: Ultra-processed foods 40:30 - Summary 42:17 - Will Tim write another book? 42:49 - Goodbyes 42:53 - Outro Pre-order Tim’s book here. Episode transcripts are available here. Check the trial mentioned in today’s episode here.  This podcast was produced by Fascinate Productions.

Welcome to ZOE Science and Nutrition where world-leading scientists explain how their research can improve your health. Why do we love food? Food has shaped the way we've evolved over the last million years. When we started to cook our food, our digestive tracts slowly became shorter as a result of more easily absorbed cooked foods. Our brains became larger thanks to this increased nutrient intake with a major part dedicated to our senses, in particular those neuronal areas related to food. As omnivores we needed a good system to distinguish edible from non-edible foods and those that were at higher risk were those that gave a bigger reward. This is why from a young age we are hardwired to be wary of bitter or sour foods that may

be dangerous and programmed to love sweet foods with energy-dense fatty or savory foods lying somewhere in between. We all know young children can be fussy eaters, but before the age of two, they are still highly receptive to many novel foods, textures and colours presented to them by their parents, enabling them to overcome their initial taste of bitter vegetables such as broccoli. If you haven't guessed it already, this isn't Jonathan. I'm Tim Spector and you just heard a passage from Food for Life, the new science of eating well. In today's episode, Jonathan and I discuss the surprising discoveries I made during the six years it took to write this book. Enjoy.

Tim, thank you for joining me today. It's a pleasure, Jonathan. Good. So I know I told you that I wouldn today. It's a pleasure, Jonathan. Good. So I know I told you that I wouldn't ask any quickfire questions, but it turns out I've cheated, Tim. I woke up this morning and I decided that everyone likes quickfire round of questions from our listeners. So I have a few which you haven't had a chance to be briefed on. So are you ready to go?

No, no, not at all. I'm going to do it anyway. The normal rules, yes, no, or maybe a one sentence answer at the most. So let's start at the beginning. Tim, you're a medical doctor. Is food as important as medicine for our health? Absolutely. Although I didn't used to believe that and most doctors still don't believe it. Did you think you had nutrition all figured out when you wrote Diet Myth five years ago? I was cocky enough to believe that. Yes. I thought that I had most of the answers. Although, in fact, I'd only scraped the surface, I think, of what's coming. So are there things you got wrong?

A few things that people have pointed out in Diet Dartmouth were wrong, but on the most part, I'm actually fairly happy that my speculations for what was going to happen in the future ended up being correct. So actually, I didn't do too badly, although I was pushing the boat out a bit with that first book. And have you changed your own diets while writing your new book, Food for Life? I have, yes. So my diet has definitely evolved. And for people who know me, it had already changed a bit, but it continues to change. And each time I discover some new interesting fact about food, it continues to be modified. And perhaps I'll never stop changing. I think that's a wonderful way to think about it. And I can think of one change we'll discuss later,

which I think will really surprise people. I'm just so pleased to be able to have this conversation with you, Tim, and mainly because it means you finally finished writing Food for Life, which I know has been a massive labor of love. And for those of you looking on the video, I have got the book, so it is real. It's here and there is some weight to it.

So this was a lot of work, wasn't it, Tim? Yeah, six years of my life, which I'll never get back, but at the same time has been very rewarding. So it's like anyone who's written a book will know this balance between pain and pleasure that books give you. But certainly, you know, you can't do something like that without learning masses about the subject. But I also realized why no one else before me had attempted such a massive feat of trying to cover

the whole of the subject in one book. And I realized that after I was about a year into it. And I really enjoyed reading it. And I know that a lot of people will enjoy reading it. There are so many things we could talk about because it covers so many different topics. But I think what would be most interesting actually is to talk about where you've changed your mind and where your view now is not the same as it was five or six years ago. And I think one of the reasons I think that's so interesting is it feels like there's so much focus on the idea that people mustn't ever admit that they were wrong or that they changed their mind. And one of the things that I love about you, Tim, is you're happy to

admit this. And I think that's so important because the whole idea of science is it's a process of getting a better and better understanding of the world by challenging our assumptions, right? Change in our mind when the data proves we were wrong. And so I think this book is your own doing science around nutrition and saying, okay, this is what the latest data says. And so if you're right, I'd love to talk about the top five foods where Tim has changed his mind and how this has actually changed what you eat. And I particularly want to do that because when I first met you six years ago, I assumed you already had the perfect diet. So I think that if even Tim can get better, it tells us that all of us can continue to improve. Absolutely, yes. And I think just it's worth pointing out that this book is different to the previous two,

Diet Myth and Spoonfed, in that it's more a practical guide to, yes, it covers the science, but it then goes into much more detail about how you can practically tell the difference between foods and what you should actually do. And I think by forcing myself to write this more focused, practical book, it did actually raise many of these questions that we don't always know the answer to, or I'd avoided when I was talking in more general terms in the previous book. So it does put the writer on the spot to actually sort of say, well, okay, how much broccoli should I eat a day? Or what is the best plant to choose? Which is the best bread, for example? And these really bring

it into tight focus as you then have to explain why you made those choices. And I think you just mentioned that the first topic I wanted to talk about, which was bread. And I think that is probably the number one thing that people ask us about in terms of food. So bread, how have you changed your mind about it, Tim? Six years ago, I thought that most breads, if they looked brown and had some sort of healthy label on it, would be generally fairly good for me. I knew to avoid very white breads or the cheap supermarket white breads. But

I thought that if it looked like decent, healthy bread, it was quite likely to be for me. And I could have, yeah, not masses of it, but certainly I could still keep it as part of my diet. And I think that was probably the first real shock that hit me was when I would take one of these brown, healthy looking loaves that have whole grain, whole wheat made of, you know, all kinds of nice stuff with occasional bits of seeds sprinkled on it. And it was only when I started testing my blood sugar responses to these that I realized that, you know, all the glitters is not gold, and that actually, underneath it, they're pretty much the same. And there was very

little difference between the brown breads and the white breads that were made in very similar ways, except the brown breads are often dyed, or they had just a few things added to make them look healthier. So I suddenly realized this, there was this huge range within this one category of bread that I was calling the same, that suddenly I had to reevaluate and had to sort of go back to basics to say, well, what makes a bread different? What is the key fundamentals about some breads that are much less healthy than the other? And that's really where I came across this idea of looking at the fiber in the bread versus the amount of sugars that are easily absorbed and the processes by which breads are made, whether it's the highly chemical process that you can make bread in a couple

of hours in a factory with a Chorley wood method, or it's made over 24 hours with a sourdough method that is the old traditional way of making bread and what actually those differences were. And I also discovered breads that I thought were fantastic, ancient breads from Italy that had been used for centuries, like ciabatta, which we see a lot. It turned out it was just a marketing invention in the 1980s, which I think- It's rather disappointing, isn't it? I did feel very let down by that, but realized, well, what else we've been fooled about into

thinking as healthy as not healthy? And I think you mentioned actually some of the labels that we often see on bread, be it in the UK or the US, are also similarly sort of empty marketing. Can you give some examples? Yeah, there are also all kinds of terms like that that are really fairly meaningless, like whole grain and full of fiber, high in fiber. Actually, the bar for being high in fiber is so low that it's pretty irrelevant. If you match that fiber with masses of starchy carbs, the overall balance means that that fiber is trivial compared to the damage it might be doing to you if like me, you've got a susceptibility to carbohydrates.

And so what have you changed? What were you eating before? And what are you doing today? Well, now I pretty much only regularly eat dark rye bread in terms of purchased, bought foods. I try and get rye sourdough, but it's not always available. But actually those rye breads you can get, do have a long shelf life, I think are quite reasonable because they really are packed with fiber and they don't give you the sugar spikes. And I also make my own sourdough bread now.

I sort of alternate with my wife. We compete a bit. And mine are all packed with various grains. I try to do multi-grain ones, so not just rye, but I put spelt and other ones that I have around. And there are even some flours where you can get 10 or 20 different grains combined. Always add nuts and seeds. And I find that a very small amount of that really fills you up much more and doesn't give me at all the same sugar spikes or energy levels. Unfortunately, my love of croissants and baguettes and bagels has had to take second choice.

So, you know, I no longer see them as stables. Which is tough because everybody loves a croissant and a bagel. So I now have them as a special treat rather than saying, well, I can have these regularly. So even if I'm in France, you know, there's no way I'm going to have these every day. But if there's a particular famous boulangerie where you can pick up your croissant or just taste a superb crusty baguette, yes, you'd be stupid not to. But I think changing that idea or treat that is in fact equivalent of a sugary treat from a staple, I think is really something important. But in general, I'm eating much less bread because

I'm much more fussy about it. And so I reject a lot of breads that I'm offered because most people in our cultures, I read bread two or three times a day. And I think it's definitely the wrong thing to do. And it's much more harmful, I think, than people realize. Really interesting. And I think it's a great transition actually to number two of the things that you've changed, which is actually not a food. The topic is actually personalization. Tell us about personalization and how your views have changed. Up to six years ago, obviously, I was very keen on the gut microbiome. I'd started studying that about 12 years ago. And my book, The Diet Myth, was all about reintroducing the gut microbiome to people and its interaction with foods.

I thought that if you just ate for your gut, then generally most things would follow. And I think that's still broadly true, that all of us can get to a certain level of healthy food by listening to our gut microbes. What do they like to eat? And in general, what they like to eat is good for your health and generally good for the planet. But within that, I think there are some quite important rules. And it was only when I did the early studies for the Zoe Predict study, we were doing pilots.

I think you did this around the same time as me, Jonathan. I did. I remember being in the hospital, having needles stuck in me like 10 times. For you, we're more used to it, Tim. I mean, you're a famous scientist, medical doctor. For me, it was like a huge shock. So I definitely remember that time. No, I did it because actually I do all the experiments that we put our twins through. That's one of my rules is that I wouldn't ask subjects to do things that I haven't already done. And so I've had bone biopsies, I've had fat biopsies, I've had all kinds of, even had colonoscopy and other things, more invasive things. So it was routine. I love that. It's like testing your

own material before you give it to the public. Yeah i think it builds trust to say well you know he's not in some ivory tower not doing this stuff uh he's seen what it's like and he's he survived so if tim can do it and uh we can and so i went into this uh not knowing really how i would respond to foods. And we had those very early primitive muffins. And this is the first time I'd seen this really big spike in my blood sugar when I had that first muffin and followed up by a milkshake. And it was in a range that I really hadn't thought I'd be at at my age and thinking I was relatively healthy. So, you know, I'm not overweight, I exercise, I look after my diet, but I couldn't change those figures, which for me, showed me this really big sugar peak and below average fat peak. So it wasn't like I could eat

any amount of fat. So it suddenly said I had to be really much more careful about what I was eating. Once I sort of knew this, I started thinking more carefully about what I should have for my meals and breakfast and how I actually felt after them. And what were you eating at that point for breakfast and lunch? And how have you changed that sort of personalized to you? I don't remember the exact sequence of events, but I was moving off the super healthy mueslis, but I was still having it occasionally. You know, these expensive mueslis you think are better for you with nuts. And I was starting to experiment with things like oat porridge, which apparently, you know, according to some of the data, had been shown to be better for some of your blood fat levels.

Yeah, I think we've all read lots of things about how that's supposed to be really slow release, healthy breakfast, right? Oatmeal for our US listeners. Yeah, so I'd already given up orange juice because I knew that was bad. And I had actually taken my blood sugars using different methods and seen that my orange juice was just as bad as Coca-Cola for me. So I'd just given up Coca-Cola, but still in this transition period, saying, well, there must be some healthy carbohydrates I can have in the morning that would work for me. And oat porridge was one. A lot of the muesli with nuts and seeds,

I thought that would compensate. It turns out that those two were still terrible for me. So I ended up with really big glucose spikes with my breakfast. And that really told me, change it. And for people listening who maybe haven't heard about this, why is that bad, Tim, in your opinion? Everyone gets some sugar spike after eating food. It's a normal response to the body. Carbohydrates gets broken down and the body gets rid of the sugar by releasing insulin. So you need a little bit of the blood sugar to go up in order to trigger the insulin to bring it down again.

And for most people, this is a little hump and it goes down again. But in some people, there's an exaggerated response that lasts a bit too long. And this causes stress on the body. Over time, it can lead to stress of the insulin system. So you might end up with type 2 diabetes. But short term, it leads to inflammation, which means that the body is under much more stress than it should be. And this can stress the blood vessels, it can stress the brain, many parts of the body just slightly in a state of tension that over time leads to all kinds of diseases, accelerated aging, metabolic problems, etc. So not something you want. It's not something you want if you can avoid it.

I mean, sometimes there are some things in life you can't avoid. But it seemed to me, once you start doing doing these experiments that suddenly you're empowered to change the way your body is responding and so you can actually make a real conscious decision to do things about it so you know eating a healthy oat porridge and seeing you had this big spike when all the experts were telling you it should be absolutely fine for you. And particularly in the US, oatmeal is seen as the holy grail of foods. It was rather strange that this happened. So I knew that really I had to get rid of, particularly in the morning, this whole idea of this carb load.

And I switched to a healthier fat protein predominant breakfast. And this was really important to me. And as soon as I started getting this full-fat yogurt with nuts and seeds, I felt much better. I didn't feel as hungry. And that's breakfast of choice now, is it, Tim? It's breakfast of choice when I have breakfast. And we may come out to that, but I've since discovered that another way to avoid the sugar spike is actually to not have breakfast at all, which I know I find easier to do than you do. Yeah, it's a catastrophe for me. But again, this is the joy of personalization, isn't it?

Exactly. And you have to experiment. And it's something I've slowly started to do more of. It's not something I just jumped to on day one. But I also try and vary my breakfast. So, you know, some days, I will still have my rye bread, but I will cover it with cheese or avocado to improve it. And this is what the personalization also adds is that as you layer on these other foods, you get an idea of their score for you. And you try and balance this out so that you can have fun, interesting, diverse food that's good

for your microbiome, also protecting yourself from excess stresses on the body. And I remember one of the things that was really striking when we were all in the hospital right that very early day is we also were joined by our other co-founder, George. And you and I both actually had very high blood sugar responses, it turns out. And George's were way lower. And so that I remember as being just like a real eye-opener because there's nothing on the outside that would have made you guess. And so for me, I remember just being sort of really stunned. i think you know similarly this has obviously had a big impact on what i eat afterwards yeah my wife can eat croissants which is really annoying you know and is that the best special belgian jeans

is it is that that you're sort of adapted to a croissant for breakfast it must be yes so but it just shows you that this personalization is definitely going to change the family breakfast. And the idea that one size fits all is obviously complete nonsense. And the idea that there is this idea of a healthy food for everybody, I think it largely goes under the window. But yeah, so this increasing personalization layered on top of my microbiome knowledge has really sort of helped me shape where things are going. But taking bread out of the equation, apart from, you know, occasionally and when I do, trying to make sure that I'm compensating for those extra spikes I get from the carbs in the bread, not only with the fiber in the bread, but also layering on other things that will delay how quickly that sugar gets into my bloodstream, I think is also

important. And the nice thing is it's actually quite fun to think of other bits to put on your food to add to it. It's suddenly like a bit of a chemistry set. I agree. I loved this spices podcast we did a little while ago. You know, I'm still playing at trying to figure out the spices that I put on my breakfast, half of which are a disaster, I have to admit, so it doesn't really know anything about spice. I think many people, I think, must be like us at home who feel like you sort of ended up in a bit of a rut, eating the same food over and over again. And I think one of the things that I've really enjoyed over the last couple of years is this push to very different food.

And my wife has actually just finished doing Zoe quite recently. And it's interesting, it's had a huge change now, suddenly on what we're eating. She's really changed what she feels is right for her. And suddenly we're just eating all these foods that I've been trying to convince her for years, we should try, but now she's got the results for herself.

She's interested. So anyway, we were talking about breakfast and I think that might be quite a good segue onto your third thing where you told me you'd really changed your mind and which I really enjoyed reading about in here which is milk yeah so I've had an on-off relationship with milk pretty much all my life I had terrible sinusitis as a kid and I was told that I should give up all dairy products by my mum's acupuncturist because milk was associated with mucus production. And so I did as I was told and gave it up for about 10 years. Amazingly, it made absolutely no difference at all to my sinusitis or mucus production. I'm shocked you're saying that your acupuncturist medical analysis wasn't completely accurate. Yes, but I'm sure I could have gone to any

number of other doctors as well. I'm not picking on acupuncturists, but people have had very strong views on milk and a lot of people do have milk allergies and seen as foreign by some people and as life-giving by others. So you quite polarized people's views. And I've sort of oscillated between the two. And certainly, I was one of the first to probably move to low-fat milks. I never liked totally skim milk. I thought it tasted revolting.

But I would go for semi-skim milk. Is that 1%? I can't remember in America, the semi-skimmed milk so one is that one percent i can't remember the in america the semi-skimmed yes i think so and six years ago i i thought oh you know what i'm gonna i'm gonna try some of these uh alternative milks because i didn't think milk was particularly good for you and you know and i knew for the planet, it was probably better to have done dairy. So I tried a lot of these other milks, soy milk, almond milk, and more latterly, oat milk. And I was using that instead of my dairy milk. But as I read more and more in my book, I changed my mind, basically. And I will either go back to the occasional bit of full

fat milk in very small quantities. So nothing like the amounts we used to have, because I don't believe that the switching was a better alternative. So as I read more and more, realized that actually milk tends to come out pretty neutral in the epidemiology studies. I don't think it provides huge benefit for most people in terms of bone health or menopause or anything else like that, but it's not negative either. So it obviously got some components in it that are good for you. And there are lots of nutrients, particularly in the fatty bits of the milk. And can we talk about that just for a second? Because I think your chapter on milk is really interesting and it's something we've also talked a bit about. I was certainly brought

up to believe that skim milk was much healthier than full fat milk. And of course, that's as usual a product of my generation being told that low fat was always going to be better. Do you still believe that skim milk is healthier than full fat milk? No, the latest evidence shows there's no clear daylight between them in terms of any health benefits. And if anything, there's less nutrients in it. And therefore, I think full fat is probably slightly better for you if you had to choose one or the other. It certainly tastes better, has a better mouthfeel to it, seems more substantial. But that's sort of where we are.

So that's sort of been involving this milk story. And I think we've largely, certainly in the nutrition research community, largely dispelled the myth that the fat in milk is particularly bad for you. I don't think anyone's shown that to any great degree. So there isn't really now a health reason to switch to alternative plant milks. They're not better for you then from your perspective, Tim? Not in my reading and my research on this, no.

And it's been interesting because obviously in my previous life, I did a lot of work in osteoporosis and there was a huge belief that calcium and milk were crucial for bone health. And that evidence has really disappeared in the last 10 years so that all those early studies have been disputed and now whether you take milk or you take calcium supplements it doesn't seem to help prevent fractures in any way so clearly we've lost that bit of the puzzle to think that's that was one really important reason to drink milk and promote milk so i think it's gone from being on both sides either really bad for you really good for you to somewhere pretty neutral that That if you like it, have a bit

of it, but really for the planet, we should be drinking less of it and probably look for higher quality stuff rather than using it as a mass drink that's going to be good for our health. And that's why I moved in a way to the plant foods, these plant milks, because I thought at the time they'll be healthy for me, but it turns out that's not true. They have large amounts of other ingredients. Compared to milk, they're much more highly processed, generally. They're not just the almonds squeezed in a bit of water. They've got all kinds of other stuff to make it look like milk. It has a sort of vague color that resembles milk and a mouthfeel that is pleasant. And similarly with soy milk. And then you've got oat milk, which for me, I discovered a while ago, gives me a very big sugar peak as well. So in a way that's relating

back to the personalization that some people will react actually quite badly. So it's a bit like having a sugary drink. As a result of this, what's sitting in the Spectre refrigerator in the milk department, if anything? Well, I'm sort of fighting with my wife on that about what's actually there. All right. So tell us the real story. Generally, i more or less cut it out and if there happens to be some milk in there uh and i and i need to add it to something i will do but i'd be probably equally happy with a bit of if there was some oat milk to add because if it's only in very small quantities i know it's not going to be particularly harmful for me, but I know that actually that is better for the planet because of its imperative benefits for climate change. But I've really gone off the need for having milks at all.

I think you can have your tea and your coffee black, and I think there are lots of reasons we should be weaning ourselves off these products, which are more habit than anything else. And if we do, just use very small amounts of them. So that's the way I change. But it's interesting how plant milks have come from being the saviour to suddenly realising, just by understanding more about how these foods are made, which was part of my research by the book Food for Life, you come to a slightly different conclusion. And in a way, it illustrates the dilemma that we're now in with food, that we're thinking about food in three ways

now. It affects on yourself and your health, which may be personalised. You're thinking about the ethics of how it's made. Are those cows really happy in that environment? Are they inside? Do they ever get to see the grass? And thirdly, the effect of that food on our planet on climate change. And I think that's why I wrote the book is so people can actually see some of the facts, make their own minds up about which of these three is important. And it's going to differ at different times in life. I think that's also important. Can we talk about number four on where Tim has changed what he eats? And that is mushrooms,

which I personally thought was my favorite chapter in the whole book. Tell us about mushrooms. Yeah, I discovered lots about mushrooms, which I didn't know. I had no clue about. I used to enjoy the odd mushroom in a risotto or with a Sunday fry-up maybe. But I didn't realize quite how many thousands and thousands of species there are and the fact that they're closer to animals than they are to plants as well. So they're not actually members of the plant kingdom. That's crazy. And about a third of the earth we're standing on is is made

up of fungi and their their mycelium their network and they incredible how they can produce these mushrooms that suddenly appear after a bit of rain and grow massively and then disappear again for another year it's incredible and it turns out they are potentially a real lifesaver for the planet if we can harness them right, because they have an amazing amount of nutrients in them and are very high in protein levels as well. So it doesn't regard which species they are. And they have this meat-like quality to them

that humans can recognize, the so-called umami flavor. So they're often used to disguise dishes, Italian sauces. They couldn't quite afford the meat, so they just put in mushrooms. And it's well known for centuries how you can do that. And it turns out that not only are they high in all these nutrients if you leave them in the sun they actually like humans produce vitamin d so rather than taking highly controversial supplements this is after you've cut them and put them in a basket or while they're still still connected to the rest of the uh the fungus well i've seen data show that both so they can

actually still produce it because many plants do actually stay alive once you cut them from their the rest of the family if you like they will continue to still be alive so we don't totally understand this but there's now done commercially so you can buy especially vitamin d enhanced ones but many mushrooms contain natural amounts of vitamin d and i think we're going to see more and more of that as if our other sources might be drying up if we're having too much ultra processed food. So that's interesting. They like to absorb the sun like we do and convert in their skins in a way,

precursors into this vitamin D, which they obviously use themselves. And vitamin D is very good for our immune system. But we know that my particular views are that vitamin D supplementation has not really succeeded in preventing any disease at all. So natural forms of vitamin D are really important. The last topic where I think you said you really changed your mind, and that is ultra-processed food. And maybe, Tim, you should just start by explaining what ultra-processed food is, and then explain how you've really changed your views about it. So the language around processed foods is complicated because

most food we eat is processed to some extent. So even something like butter or milk can be considered processed because it's not just eating the raw plant or just cutting that bit of meat from the animal and eating it. But what we mean by ultra processed is when the food itself no longer resembles the original ingredients so that you are using extracts of plants or meats that no longer are the same as those original members. And you're putting them together in a factory in a way that you lose all the structure of those original foods. And you're just taking bits of them from a sort of chemistry set. And they tend to have at least 10 ingredients. And to make them stick together, they've often got these glues or gums or thickeners

to make them seem like real foods again. So they're like reconstituting these foods. And this is unfortunately what constitutes 50% of our diet in the UK and 60% of our diet in the US. Which is an enormous number, right? So you're saying, you know, half to well over half of everything you eat is this sort of rebuilt food instead of something which bears any real resemblance to the diet that we clearly ate until 100 years ago. Absolutely right.

And not every country does this. So there are countries in Europe and Mediterranean, like Portugal, that only have 10% of their food in that way. So it's definitely something that affects particular countries that maybe lack to food culture, but also had very strong business links and lobbying links of the food industry to point us in this direction. And the fact that we went for new, modern, scientific foods that may be easier to cook with and cut out a lot of those old time-wasting methods. But at what cost? And I think when I first started writing this book six years ago, the emphasis was all about, oh, they have high in sugar, high in fats, high in salt.

And that basically, if you reduce those three things, you can make them healthier. And that's still the main establishment government approach to ultra processed food and one that the food industry is quite happy with, because they can keep substituting different chemicals to reduce the sugar by artificial sweeteners. They can reduce fat levels by increasing carbohydrates and other sugars and sugar alcohols etc and they can reduce the salt by again tampering with the structure of the food and using different preservatives so all of it you can get round but I think what I found was that there was some new research showing that ultra processed food works not through those the bad effects of those chemicals,

those three macronutrients, if you like, but actually it's the whole process. It's these extra chemicals that act in two ways to really harm us. First is our gut microbes through the chemicals like emulsifiers and thickeners and artificial sweeteners that in most people, and this might be personalized as well, our gut microbes react to and produce chemicals that make us sicker than if we weren't eating them and might make us more hungry, might send signals to the brain to overeat and put on weight and generally mess up our gut microbiome. So basically there are chemicals in this, just to make sure that we're all following, you're saying now you feel these chemicals in this ultra processed food, which is sort of directly

triggering actions in these trillions of bacteria, which are then creating their own chemicals that really affect our health and our brain and things like that. Is that what you're saying, Tim? Yes. So it's not a direct effect. As you said, it's through our gut microbes, which I think we need to think of as like these pharmacies where they're producing chemicals for us instead of our body. And sometimes they produce the same chemicals that our body produces,

but through an alternate pathway. And we're just learning more and more about all the things they produce. So this is a very new science, but it's showing us how things that we thought were completely inert, like artificial sweeteners, like carrageenins, which are like thickeners or other lesser thin emulsifiers, sucralose, they can't harm you because we've done the studies to show that. It doesn't cause cancer or anything, but it does mess with your body. And it does that, we think through the gut microbes. But the other convincing bit of evidence for me was this study from the NIH. Kevin Hall's group were compared in a very strict environment in a lab. They gave, for a couple of weeks, people two different diets. One matched for calories completely, one a whole food diet made from real food,

and the other a copy of it made from ultra-processed food. And they were both equally satisfying for the participants, but the group that had the ultra-processed equivalent kept saying they were hungrier and they went back to eat more and more every day. So they were overeating by about 200 calories a day. So there's something else in that food that's nothing to do with the calories, nothing to do with the salt, the sugar, everything else, because they were matched. That is telling the brain, eat more. And we don't know if that's direct or through the gut microbes. But once you really absorb that information, you think, gosh, if I'm having this every day of my life

in some form, this is perhaps why we're in such a mess in countries that have high ultra-processed food percentages in their diet, like the US, like the UK, like Canada, Australia, and Germany in Europe. And that's why we've got part of this problem because we've just seen it as a reductionist idea. Oh, we've only got to change the salt for, say, potassium. We've only got to switch the fats for proteins and a bit of carbs. We've only got to take the sweetness away and add other chemicals. That changes nothing. And so I've really become much more anti-ultra processed food. And that's a big shift, isn't it? That you're saying, you know, I think, you know, I remember when we first talked that you were particularly concerned there was no fiber in it, so it wasn't positively feeding the bacteria. Now

you're talking about it almost as if we were taking a drug. It sounds almost like you're describing what would be happening if I was taking a medical drug that I don't need. We all know that all these different, many drugs have side effects. right? They say on the label, you know, may cause obesity or may cause nausea. If I play that back, Tim, you're really describing this as if these are sort of like medication, but we are not being prescribed it by the doctor, right? We're just buying it at the corner store and eating it because it tastes delicious. Yeah. And it's been designed by really brainy people, brilliant food scientists who have spent 30 years now trying to create this perfect mix of chemicals that satisfies your taste buds and makes you want to eat more of it. And that's what they're paid to do. And they do it

brilliantly and they're doing it ever and ever cheaper. So using cheaper and cheaper products, more synthetic products to do that with really no restraints at all. Brilliant. I'm going to try and do a quick summary of what has covered a lot of ground today and correct me if I get wrong. So I think the first thing is that Tim thought he really knew a lot about nutrition and it just goes to show how complex it is because this book has really led you to change your mind about a lot of things. On bread, that you've really changed your view. In fact, a lot of bread you thought was healthy, you really got to look beyond the label. The second thing is around personalization and discovering that your own results were

very different from lots of other people's. The third is milk. So since your acupuncturist convinced you to give it up, you've been on a lifelong sort of in and out of milk and that today you sort of ended up on a sort of neutral view on this. Then you talked about mushrooms and we heard it here. We'll all be eating many more mushrooms in the future. And then finally, I think you talked about ultra processed foods. This is half of our diet or even more. And that you're not saying we can't have it ever, but we need to really think about this as having much more impact than just having, you know, some sugar in something that we made ourselves at home.

Absolutely. I think you summarized it beautifully. Brilliant. Well, what I think you summarized it beautifully. Brilliant. Well, what I would say, go on, Tim. There's plenty more. Yeah, but you've just scraped the surface of what's in the book. So I was going to say that. I was going to say, I think we just scraped the surface.

There are so many chapters we haven't touched on. If you're interested in fish, you have to read the fish chapter. If like me, you really like fish, I definitely can't recommend the book enough. And again, in the show notes, we'll make sure that there are links there.

Tim, thank you so much for coming in. Thank you so much for continuing to challenge yourself as well as everybody else in terms of what is the latest science on nutrition. And I think the final question is, are you done? Every time you do a book, it seems like it takes a lot out of you. Are you done or is there another book in Professor Spector? I think from what I heard, it's a bit like childbirth. You need a little break,

but then you forget all the pain and you come back and do it again. So we'll see. This will certainly keep me going for a while, but there are bits that I left out of this book because it got too big that will definitely be another book. But I'll leave it at a safe distance to recover until then. Brilliant. Tim, thank you so much for spending the time with us. My pleasure. Thank you, Tim, for joining me on Zoe's Science and Nutrition today. I hope you're as excited as I am about Tim's new book. If based on today's conversation, you'd like to understand what personalization means for you, then you may want to try Zoe's personalized nutrition program. Each member starts with an at-home test, which is very similar to the tests that Tim was talking

about today. And those tests help you to understand your own biology and compare you with thousands of participants in our science studies. We then create a personalized program to improve your own biology and compare you with thousands of participants in our science studies. We then create a personalized program to improve your health. If you're interested in learning more about Zoe, you can head to joinzoe.com slash podcast and get 10% off your purchase. If you enjoyed today's episode, please be sure to subscribe

and do leave us a review as we do love reading your feedback. If this episode left you with any questions, please send them in on Instagram or Facebook and we will try to answer them in a future episode. As always, I'm your host, Jonathan Wolfe. Zoe's Science and Nutrition is produced by Fascinate Productions with support from Sharon Fedder, Yela Hewins-Martin,

and Alex Jones here at Zoe. See you next time.