ZOE Science & Nutrition - How ultra-processed foods wreak havoc on your body

Episode Date: April 27, 2023

Ultra-processed foods have become ubiquitous in modern diets. Many of us eat them regularly without understanding their potential impacts on our health.  From hidden additives to addictive properties, these highly processed foods can pose risks.  Navigating the complex world of ultra-processing can be challenging, and many people struggle to understand what to avoid, how to break unhealthy habits, and make positive changes to their health. In today’s episode, Jonathan is joined by a special guest, Dr. Chris van Tulleken, to explore the science behind ultra-processed food. Dr. Chris van Tulleken is an infectious diseases doctor at University College Hospital, in London, and one of the BBC’s leading science presenters.  Chris shares the groundbreaking research from his own lived experiments, including the now famous study with his twin brother Xand. His book Ultra-Processed People is out now. Jonathan and Chris are joined by ZOE regular Tim Spector. Drawing from their combined expertise, our guests provide practical tips and advice, empowering listeners to make informed choices and take control of their diets. Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:31 Introduction 02:14 Quick Fire Questions 05:25 Start of Chris's journey in nutrition 06:47 Discordant twins - How can twin studies help us? 08:51 What part do genetics play in our differences in health? 12:52 What were the potential consequences of weight gain? 15:20 What is ultra processed food (UPF)? 16:54 What's the difference between processed and ultra processed food? 18:52 Is ultra processing purely about profit? 21:13 Examples of ultra processed foods (UPF) 23:13 ZOE UPF survey - How much does the ZOE community eat? 25:28 Are the products that say they're healthy lying to us? 26:12 Are certain ingredients hidden by UPF? 27:44 Is low fat yoghurt that good for us? 30:39 Is UPF just junk food? 32:56 Kevin Hall’s UPF study 34:19 What makes UPF addictive? 36:34 Chris' ultra processed food experiment 39:12 Could food manufacturers make healthier UPF? 41:23 How do we solve the issue of UPF as a society? 45:26 Practical advice for cutting down on UPF 51:37 Summary 55:15 Goodbyes 55:27 Outro Follow Chris on Twitter: https://twitter.com/DoctorChrisVT Follow ZOE on Instagram: https://www.instagram.com/zoe/ Episode transcripts are available here. Is there a nutrition topic you’d like us to cover? Get in touch and we’ll do our best to cover it. 

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. On a summer day in 2009, two young men walked into St Thomas' Hospital in London. They looked incredibly alike, these two young men. Both were six feet tall. Both weighed around 80 kilograms or 170 pounds. Both were in fact genetically identical. Twins participating in a groundbreaking study run by my friend and Zoë co-founder Tim Spector. Fast forward a decade. If you'd seen these brothers standing side by side, you'd have been forgiven for thinking they were not related. Why? Because one twin, Zant, now weighed over 120 kilograms or 270 pounds, while Chris's weight was essentially unchanged.

So what had happened? During this time, Zantnd had gone to the US and switched to a diet of almost entirely ultra-processed foods. We used to think it was the calories that was the problem. It's in fact only in the last three years that new research has revealed that ultra-processed foods may be directly responsible for causing obesity and severely damaging our health. Today, one of those twins, Chris Van Tolken, is on a crusade to educate us on the realities of eating ultra-processed food. Chris is a medical doctor, broadcaster, and the author of a brand new book, Ultra-Processed People. He joins me and Tim Spector to talk about it. more than 15 years ago yeah so and does he look any older he actually doesn't which is my hairline has changed and tim's has not well he was you were school boys when you did your first you're

presenting role when on twins it's his amazing microbiome that's what it is chris so we have a tradition here that we always start with a quick fire round of questions. And we have some very simple rules. You can say yes or no, or maybe, and a one sentence answer if you absolutely have to. All right, I'm going to start with three questions for Chris and then three for Tim. So Chris, does ultra processed food cause obesity? Yes. It's responsible for pandemic obesity. So it causes, it is the primary cause of obesity at a population level. You notice, I notice already you're good like a professor at like quite a long one sentence answer. Okay, we'll give you that for the first one. Was that too long?

No, no, no. You know, it's... The academic answer. It's the academic answer. It's good. I wanted to say so much more. The proximate causes of obesity are really... This is always hard for scientists.

All right. Can ultra-processed food rewire your brain? Yes. How much of our food is now ultra-processed in the US and UK? So I get my one sentence. Yeah. That was a tricky one at the end for you. In the UK, on average...

UK and US, yeah. In the UK and the US, on average, more than half of our calories, on average, come from ultra-processed foods. Which is obviously enormous. Brilliant. Tim, do scientists understand how ultra-processed foods damage our health? We're beginning to. Can you undo the damage from ultra-processed food if you stop eating it?

Yes. And finally, can ultra-processed food ever be healthy? Unlikely, but I'm not saying it could never be. Chris, you got one on that one? I think unlikely is a really good answer. I mean, I'll tell you what, just for difference, I'll say no. Fantastic. And we're going to come back to all of those things. I hope that's teed you what, just for difference, I'll say no. Fantastic. And we're going to come back to all of those things. I hope that's teed up. It's pretty interesting,

right? People talk about this food as literally causing obesity, causing rewiring of the brain. I think this is all stuff that I had no idea about a few years ago, and I'd love to unpick it a bit through this. But before we do that, I'd actually love to, let me go back to sort of the beginning of this story and why you're interested in nutrition, because I think it really ties in with the first story that Tim told me when I first met him, because of course, Tim has been doing this twin study for 30 years and looking at differences between identical twins. And so I'd love maybe if you could talk a little bit about the story about, you know, your own experience as being an identical twin and how that's, I guess, started to intrigue you with nutrition.

And maybe Tim can tie that in a little bit to his own journey from, I guess, genetics as destiny to this idea that actually there's a lot more than just our genes that shape our health. Your first DEXA scan you had in the department on your brother. I mean, Tim, you know, really weighed carefully, you know, measured me and my brother. And I think that was at the beginning of quite a long interest in nutrition. And how long ago was, when was this? We think that was about 2007 or 8.

So more than 15 years ago. And as a result of that program, I found out that I have really all the major genetic risk factors for obesity and bearing witness to that. And Tim remembers this very well is that my identical twin, who is my genetic clone, when lived in the States for a year in fact he lived there for a decade and he had a quite a stressful time there and he put on around 30 kilos 30 kilos huge amount of weight and um and i was protected by several things the uk food environment by i think i should just mention for those who are on audio lay chris doesn't look like he has put on 30 kilos at any

point in his life i am currently i, at the low end of overweight. So I hide it well because if you're a bloke, people don't look at you in the same way and you can wear a baggy jumper. But I'm at the low end of overweight at the moment. But no, Zahn became very heavy. But also, I'm an infectious diseases doctor and I did a lot of work in public health and global health where nutrition is what underpins early death for particularly children all around the world and they get severe infections. And so this, having this brother who was really living with

significant obesity and seeing my patients being very affected in particularly in low income countries by poor nutrition gave me a real interest in how we should feed ourselves better. Yeah. And I remember having an interest then in discordant twins as well. Discordant meaning? Meaning where one twin, they differ in whether it's height or weight or diseases. So there's lack of concordance. I was intrigued at the time about what the reasons for that would be. Because it seems strange because they were genetically the same. Generally, people think of identical twins as everything's identical about

them. They smile the same way, they pick up their beer the same way, they giggle the same way, everything looks the same. But when you actually get to diseases, they die at different times, they get different cancers. Actually, longevity is rather different and the aging process is different. And we've never really explained why that was. And so, examples like Chris and Zan were fascinating. Was it just that one went to the US and the other one didn't? Were there other emotional reasons or there's some physiological thing or something earlier in their life? So to me, twins have always been this amazing model where you can sort of separate all the

differences. So these are two clones who lived virtually first 18 years doing exactly the same things. And if they're different, what was it about them? So I think it is a fascinating natural experiment that we were seeing in real life. And then again, both the twins were interested in their own destinies, if you like, and what happened to them. Hi, I want to take a quick break here and tell you about something new we've created, a free guide that will kickstart your journey to better gut health.

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To get yours for free, simply go to zoe.com slash gut guide. Is it fair, Tim, at the time, I think you said, because you were running the largest twin study in the UK, one of the largest in the world, that we had the greatest discordance in our weight of any twin pair that you'd ever encountered in the scientific literature. There was a bigger difference between us. I think it was 26 kilos at the time? Certainly that was true for males of your age. I think we have seen other ones bigger than that, but certainly in the young males, it was pretty extreme, yes. And that was sort of quite shocking, really. And was this part of what was triggering your realization that it couldn't just be genes that were driving our health, Tim? When I met you much later, you... Certainly I realized it couldn't just be genes in the sense that they both had identical genes in every cell of their body.

At the time, I thought it could be something called epigenetics. We probably might have discussed that at the time where little chemicals and things might just tweak your genes. So chemicals get stuck onto your genes and that makes them produce different proteins. And I was sort of going down that route. But in 2008, no one was discussing microbes and the gut microbiome and that as a potential route and a difference. And also people you know we're only talking about portion sizes and oh in america that you just get bigger amount of fries than you do in the uk so that must be the reason so it was quite primitive in terms of the ideas we had and it might have just been oh well

zand had been having extra calories that's why why he'd got bigger. We didn't really relate it to anything much more scientific than that. We didn't think there was a different type of food available in the States in greater quantities. And Zand, it turned out, was eating a diet approaching 80-90% of ultra processed food for a really long time. So it is amazing. I remember when I think, because, you know, I'm not an identical twin or any sort of twin. And I remember when Tim was explaining to me this, first of all, it is amazing because identical twins are sort of like these experiments, right? Where you've got two individual with the same genes and the same upbringing, and then different things happen to them in their life, particularly, you know, after they're 18 and you see the difference. And, you know, Tim was obviously talking about much broader set than just you and Zand, but the way that you could see these like really big differences and then in his experiments

get to the point where, you know, in laboratory conditions, feed identical twins exactly the same food and see these really different responses in their blood. And this was the thing that really triggered this idea of Zoe really, and about being able to turn that into large scale and personalization. And so, you know, I think it's fascinating to then, you know, to be talking about this as an example, because for me, it was a big part of what created this podcast. So it's fun to have you on the podcast, because I think that meeting with Tim and the 12,000 other twins is sort of what made this podcast ever happen. It's quite cool to me.

I don't think I quite understood that I'm a tiny part of the Genesis story of this. Yeah, not just a tiny part. No, quite a big part because it was those exceptions to the rule that for me was my aha moment in you know in my in the career of thinking well a it's not you can't say it's all genetics and then b seeing these really great examples like you and your brothers trying to say well i've got to find out why you know because it's not genes and i discovered it probably wasn't just epigenetics and so there must be something else and that really led me to the the gut microbes and gut health and everything else sort of followed because once you've got that then you start thinking about food in another

different way to the old-fashioned way and we start getting back to you know thing that's now interested you food quality and and all this and it's, yeah, it's these amazing, except natural, experiments that you and your brother. And if you could do an experiment, a great thing to do would be to take some identical twins and leave one genetic half of them in the UK and move the others to Boston. That would be a nice experiment. So Zahn and I unwittingly did this for Tim. Oh, that's lovely. I didn't kind of know that,

but it's nice to understand my place in the Spectre narrative. Thanks very much. And Chris, I'm assuming that part of the reason that this really struck you, it wasn't just, oh, my twin is overweight. You were worried about the consequences that came with that weight gain. Is that right?

I mean, he got COVID during the pandemic. We were making, I was working in the hospital at UCLH. We were making a documentary where he was out doing public health stuff and I was with the infectious diseases team. And he came in because his heart was in a strange rhythm and we had to, my team had to stop his heart and restart it because the covid had given him this this this heart problem it's pretty terrifying that it happened again and again and again and eventually he needed an operation but that was almost i mean insofar as we can know and tim would tim would have a very good view on this but probably because he was so much bigger than me so there was a there was a thing where you know he's we're terribly close you know he's my he's my best friend i would i would um there's a moment where you're sort of watching his heart being restarted

i feel actually i'm welling up a bit but um uh it was yeah it became a real emergency that he'd been he'd been the funny one and he he didn't look bad and it wasn't affecting his career because because it doesn't. But yeah, it became a problem in the family. So there was just a very acute reason. But this was the focus of an argument for a decade. I'd been nagging him. I remember Tim saying when we made this documentary, expressing some surprise there was this very big difference between us.

And I tried to use that as leverage for i think i said something horrible like you're a disgrace to your genes didn't know that sort of it was which is very unsympathetic at the time i regret we were in a different we were in a different national conversation about weight and stigma and actually the quote you're a disgrace to your genes became the centerpiece of the trailer of the promotional material because it was such a powerful idea that someone had these, clearly with the same genes,

I wasn't gaining weight. So what was it that Sam was doing? And I think that's not something you would say today, right, Tim? No, absolutely not. Because that tells you something about the journey. And actually I think it's a brilliant transition

to talking about the topic in your book and a topic that Tim talks about all the time, right? Which is ultra processed food and more broadly how the food is having this direct effect. Could we maybe just start at the beginning? So, you know, I think many people have no idea and we did a little poll actually, like nobody really understands what ultra processed food is versus processed food versus food. Chris, you know, could you maybe start by just helping us to understand very simply, like what is ultra processed food? So there's this long formal scientific definition because it's a category of food that was developed to do research with, to study diet and its effects on health. But it boils down to if it's wrapped in

plastic and it contains at least one ingredient that you don't typically find in a domestic kitchen, then it's ultra processed food. So that's the shorthand way of figuring it out. And this was a definition that was developed by a group in Brazil in 2010. And since then, we've had now over a decade of really really good increasingly robust research including a very good clinical trial that has linked ultra processed food to early death cancer weight gain and a whole host of other other problems i think this is the nova classification is that right that you're referencing could maybe the two of you help to sort of step us through a little bit from stuff that i think we all feel pretty comfortable isn't processed because it's like a

fruit or something you know you're eating it completely off as it came off the tree to the other end where i think we all sort of know that if it's got 50 ingredients in it and it's bright yellow and it lives for 100 years and you can still eat it that's probably at the ultra processed end and i think we're all deeply confused about everything which is like 95 of what we eat right which is somewhere in between could you could you maybe just help us to step through so i think they have a few classifications don't they to help us understand a bit more um how that works so i would say that the boundary between ultra processed food and just processed food, which we think is fine, is quite a blurry one. And particularly in the UK, we have a huge number of products where you can buy a lasagna lots of places and it's it's wrapped in plastic. But the ingredients, while it's a long list, there will be nothing you wouldn't have in a normal kitchen there.

And there are these questions about, well, is that ultra processed or not? And I think this is the discussion that a lot of people who've read my book come to me with is going, what about this product? Is this okay? And those products in a sense, the most interesting because the classification system wasn't invented to decide about one particular sausage roll or another, But the shorthand of the ingredient is a pretty useful one. If it has an additive that you don't typically find in your kitchen, then I think it's useful to say it's ultra-processed. I find that for me, what I'm interested in, and I think there will be some of your listeners

who are living with significant obesity or living with a diet-related disease, and they may want to take an approach of abstinence. For those people, having a definition that allows them to exclude this entire category from their diet would be useful. I think it is possible to do that. My rule of thumb is if I'm in doubt, it is ultra processed. If you're wondering about this biscuit or this lasagna or this bread, it probably is. But one of the arguments that the food industry is starting to mount, and there's a huge opposition to my book and to a lot of my work by the food industry, is that, well, humans have been processing food for millions of years.

And this is absolutely true. Since we first cut a chunk of meat off a mammoth and we started cooking probably over a million years ago, that is food processing. And we've been pounding and grinding and extracting and salting and smoking. And all this has been happening for hundreds of thousands of years. And it seems to be fine. But ultra processing is a very different thing. Ultra processing is about broadly taking traditional foods and designing them with the cheapest possible ingredients to be very hard to stop eating and doing that for profit that's that's the very important part of the definition is ultra processing is about

profit it's not about nourishment and i think giving some examples here is useful so cheese is a processed food, okay? So we're not talking about those as being problematic because virtually all our food is to some extent processed. But it's when you're replacing the natural ingredients with the extracts of other foods and extracts of chemicals to mimic the original foods using what we call edible, industrially produced food-like substance. And I think it's that

substitution. I was just laughing because I feel like food-like substance already. I don't really want to eat food-like substance, do I? I'd rather eat food and you know it's exactly right so it's you have these ingredients you wouldn't recognize in your kitchen they're all there to make that food seem like the original as much as possible but using the cheapest possible group of ingredients that allow you to manipulate it give it a massively long shelf life and make you overeat it. And so that's really where we are. And the food industry doesn't want a definition of it because that would make it very easy for them to be criticized.

So they're always countering these discussions with saying, aha, we've got some examples of something that isn't, and you're saying it is. But it's quite easy to define, I would say, 98% of foods in this way. There are maybe a couple of percent that we can argue over. So I think what you're saying is that there's this sort of clear scientific definition, though relatively recent, and I know from our own own work there's probably still more work to make that better but it's quite complex and so this is a sort of simple sort of rule of thumb if you like as a way to say i'm navigating the grocery store you know the shop as a way to under or my fridge to understand what is ultra processed and and tim's tim gave the example of of cheese is a

brilliant example of a processed food that for a long time we thought was a bit unhealthy. Butter also works as an example because butter is something we made probably 8,000 years ago, 6,000, 7,000, 8,000 years ago. Margarine was the first probably mass-produced ultra-processed food. There was solid fat shortening. And it was a way of turning waste oils, cotton seed oil, into an edible product that you could put in the human food chain and generate enormous value from. And so fake butters, margarines essentially, were the first set of these synthetic foods where almost all the molecules in the food product are synthesized. And we've never encountered molecules quite like this before and is that a very important part of the story that these are you know new chemicals if you like that our body hasn't been exposed to for thousands of of years that our microbes haven't

exploded is that is that a very important part of the story or this is not clear or well i think it's an emerging part of it. I don't think we've studied it well enough. And until recently, we just assumed that these chemicals were inert. So the food industry tells us that, oh, like saccharin, it's completely inert, zero calories, just passes through your body straight out of the toilet. You don't have to worry about it. Absolutely perfect. And that's been the general theme of these industry-produced chemicals. And most of the artificial sweeteners, for example, come from the petrol industry. So they're not made anything you'd eat. They're made in laboratories. And I don't think we know

the answer to many of these things, but I think it's quite likely that these do have long-term consequences. We just haven't studied them properly. But it's just one part of the story. It's not just those substances. It's other things which we're still beginning to understand. So we can unpack more in a second then. Just before moving on, we did a little survey of the Zoe community on social media to ask how much ultra-processed food they believe they ate. And interestingly, 84% said they eat little or no ultra-processed food.

And my question is, is that typical? And is it possible they might be eating more ultra-processed food than they realize? Are your community lying to you? We trust the Zoe community. I think that they will be telling you what they think is the right answer. They're probably healthier than the average UK population. People who listen to this podcast are more health conscious. So you might expect, which the official figures of,

57% of the calories eaten in the UK are ultra-processed is the latest data. And in the US is? It's over 60%. And for children, it's higher. So we think 10% more in children. So the average person is going to have more than half their calories that way. So it's a slightly different question. How many of your calories are that way?

Or I never have them. But I think that is an underestimate. And I think people, I don't think they're that healthy. I think it's very difficult to avoid ultra-processed foods if you know what all of them are. And it may be that these people don't realize that in the morning when they drink their orange juice and they have their muesli and they have other breakfast cereals, for example, or their instant porridge, they're eating ultra-processed foods. That's amazing. So breakfast cereal is an ultra-processed food? I would say almost all commercially available breakfast cereals are ultra-processed. Almost

all supermarket bread is ultra-processed. Almost all flavored yogurts are. And the areas they might be not noticing their consumption would be the very typical lunches that we go and have in the UK. Lunches, a packet of crunchy things, might be some popcorn, a sandwich, and a drink. And particularly if you get it from the fancy shops, and we can all know the names of them, they're widely available up and down the country, that's still all ultra processed. It all contains maltodextrin, dextrose, the bread is full of emulsifiers, there are flavorings. So even the sandwich that you might think is like it's just bread and like this plain... It might be a vegan, falafel, organic, whole grain, but the bread will contain emulsifiers and the condiments particularly will contain thickeners or maltodoners.

Even if it looks brown because it's been dyed brown, it looks like a granary, healthy, seedy loaf. Generally, it's been made to look exactly that, but underneath it, it's full of these chemicals. So yes, I think many people don't realize the extent to which they're surrounded by stuff, even with healthy veneers. Anything that says it's healthy on the packet is nearly by definition unhealthy. It's a great rule of thumb that, isn't it? If there's a health claim on the packet,

it is almost certainly ultra processed. Chris, I read that in your book. I loved it because I thought for a minute and I was like, that's actually so true. Every time these things say- I haven't found an exception. High protein or the one that actually my personal experience, because I've been looking at this a lot more over the last year as you guys have been talking about this more is sort of sugar-free and no added sugar, which I think like most consumers, that sounds really good. I'm buying this for my little girl who's three, for example. You know, that sounds like the right thing. It's sugar-free or no added sugar. I've now started to learn to turn over and look at the ingredients. And instead of seeing sort of

three ingredients, you suddenly find 15 and it's stuffed full of sweeteners and they haven't had to put on the top. We put in lots of sweeteners instead of sugar. They've just said no added sugar or sugar-free. So my favorite example, because it's been the one that's been most shocking to me, is actually just looking even at plain yogurt. And plain yogurt should basically have milk in it, right? And what's amazing, I've now realized, is that most of the plain yogurt you go and look at when you turn over, it's got like half a dozen or sometimes even 10 ingredients in it.

And it's right next to the one that only has milk in it. And it's impossible to tell. There's nothing on the, you know, until you actually go and look into the ingredients, they look the same. So there's a sense, I think, in which it's... It says low fat, you're more likely to have fake yogurt than if it's full fat. But there's something really hidden, I guess, is what I'm saying about these ultra processed foods that it seems to have happened without it being very visible to us. Is that? That's completely right. And if you consider one of the things like the illusions of our sort of food supply system is that it exists to supply food to us. And that isn't the way it works. It exists to extract money from us. And so low-fat yogurt, the genius of low-fat

yogurt is you can sell your yogurt at a premium price because it doesn't have fat in it. And you can add a very cheap modified maize starch to give it a creamy feel or a xanthan gum or a guar gum or a locust bean gum, any of these gummy things that give a fatty mouthfeel and then some other stuff as well. Meanwhile, you've still got the fat and you can then use the dairy fat, which is the highest price commodity fat you can have to do all kinds of other things with. And you can extract some of the protein and put it into whey protein. You can put it into muscle drinks. So you're adding much more value to your commodity milk by putting different aspects of it in the food chain.

So yogurt's this brilliant idea of repurposing waste and extracting more value, but none of it's done with an eye on our health. And most people still assume it's just because it's got high fat. Therefore, if I pick the low fat one, that's going to be fine. And this is this huge misunderstanding, cleverly done by the food companies as well. But also the scientists haven't really applied themselves to looking at this because we've had this rather reductionist view of nutrition, as I'm always going on about, you know, into calories and the macronutrients, which misses the whole point.

So reductionist meaning like, I just think about it as a set of individual components. Yeah, food is simple. If you understand the calories, you know, the fat content, the sugar content, you don't really have to worry about anything else. And that's what's got it into this huge mess where we're so ignorant about food that we treat it all the same. And therefore, we can slip into this, the majority of our food being this poor quality, ultra-processed, industrially made edible stuff that ticks the right boxes and has health claims on the front, is actually killing us and causing us all kinds of problems that isn't related to those

macronutrients. It's all the other chemicals that Chris has been talking about, these other extra bits that have been added and the effects they have on our body. And that epidemiology, which by itself is never quite enough, has been added to by this clinical trial done by Kevin Hall of the NIH, which, I mean, you can describe in more detail exactly what that, but that was a real game changer. That was about three years ago. And just giving people ultra-processed food and the identical equivalent in calories and macronutrients of properly made food that had some really shocking results, even to the people who did the study. I mean, the question you're asking is so important.

Is ultra processed food just fatty, salty, sugary food? Is it just what we usually think of as junk? And in fact, one of the papers Tim's, I think, referencing is produced by my PhD student, a guy called Sam Dickin at UCL. And he did an analysis where you can do these statistical controls when you look at all the data and go, yeah, but what if we account for fat and salt and sugar and fiber and dietary pattern? And in every single case, whether they were looking at early death or cancer or strokes or heart attacks or dementia, in every case, when you make that adjustment, the effect remains the

same. In other words, it's the processing. It isn't those nutrient contents. And Tim talks about, you know, we think of diet as simple and that's, I mean, I think you've been the person who's sort of influenced our national thinking about this more than anyone else. There's this incredible statistic that we've never been able to extract any molecule from any whole food and find that it has a benefit in healthy people. So we know that walnuts are good for us, whole grains are good for us, Mediterranean diets are good for us, vegetables are good for us, fruits are good for us. But if you extract the lycopene or the molecules from red wine or the vitamins and you give them to healthy people, they don't have a health benefit.

So food as a complex substance is really health giving and life giving for all the reasons that your listeners will know. But the individual nutrients are not what make it healthy or it turns out what make it unhealthy. So when you make a lasagna at home, you can make a salty, fatty, even sugary lasagna, and it will not have the same effect on your physiology or your health or your brain or your risk of heart disease as if you go and buy a very similar sounding ingredient lasagna from your local supermarket wrapped in plastic. And that's the genius of the scientists who came up with this definition was to realize that those two foods would be different. And Chris, because we talked about-

I didn't talk about Kevin Hall, sorry. Oh yeah, tell us about Kevin Hall. The Kevin Hall study, I think, was this real game-changing study because he didn't believe the results would show anything. I think that was the really cool bit. He was actually not a believer in this until he did the study.

And he had these two groups of people who were basically locked in a hospital for for two weeks they couldn't escape they were given these these food regimes and amazingly they they liked both equally that's such a crucial detail is they didn't prefer the ultra processed food and so that and one lot uh so they're eating these ones, identical calories, identical macronutrients, you know, reasonable. They added fiber to the ultra process to sort of give it a bit more oomph. So it wasn't, you know, obviously unhealthy.

And the key point, I think, was that they noticed that the ultra process group kept going back for seconds. And over the course of a day, on average, they were eating an extra 500 kilocalories a day. And I think this, to my mind, is you've got all these individual chemicals, but together, this effect on the brain and the appetite system, and it explains why we've all gained weight, we're putting on fat all the time, getting more diabetes, and we can't explain that with really the amount of calories we're eating overall. And that just shows you these foods are designed to make people overeat, to overcome our natural appetite fullness signals in the brain. For the book, I spoke to loads of people within the food industry.

And when they kind of tried to see it from their perspective, and they all said the same thing, which is in the UK for a very long time, we've had enough food. If you are going to make money and generate particularly growth as a food company, you have to sell more and more and more food. You have to make food and more and more food. You have to make food that people cannot stop eating. And through kind of, we started making this food in bulk in the fifties and the sixties, the seventies. And since then, this food has been iterated through marketing, development, back to the lab, tasting trials, focus groups. And every year this happens. And so the food, it's not being done in

an evil way or a cynical way. It's just, if you're a breakfast cereal company and you've got box A and box B and your tasting group eats 5% more of box A, that's the one that goes to market. And then you do the same the next year and the next year. And so over 50 years, you find that whether it's lasagna, your breakfast cereal, your cake, your buns, it all becomes impossible to stop eating. The show you're listening to right now that's providing you the latest evidence-based health and nutrition information from the world's top scientists, while making it takes a lot of time. We think it's well worth it, all in the name of improving your health. All we ask in return is this. Send a link to this podcast to someone you think would benefit.

And if you haven't already, click follow this podcast wherever you're listening right now. Okay, let's get back to the show. You described a bit like you might be describing something to a gambler, like the slots machine that's getting more and more addictive with more bells and whistles and higher prices step by step. Is that actually how you're thinking about it? I don't know about Tim's thinking on this. Food addiction has been very unfashionable scientifically for a long time because the problem with saying something's addictive

is the only solution is abstinence. We know that moderation doesn't work for any addiction and you can't be abstinent from food. One of the really nice things about the ultra processed foods definition is that aside from the fact that it's the only food many people can afford, it's the only available food for many people, at least in theory, you can quit it. And the research I think is very persuasive. And I went into writing the book feeling a little bit skeptical about the addiction side of things. I was very persuaded by a lot of the research that shows that for people who experience food addiction, the ultra processed foods they're addicted to are as addictive as cigarettes, drugs of abuse or alcohol. And I would

say that was true of me. So I have definitely had a relationship with certain ultra processed foods that was pathological, that was addicted. And I want to sort of, I don't want to leave this without asking about your mad scientist experiment of one, because it made me think about those things when you discover people like discovering smallpox inoculations. So Chris, you decided to do an experiment on yourself for 30 days of, I think, eating 80% at least of your food as ultra-processed. That's right. And I did it. It was an experiment of one, but we did it quite formally. So I did it with a group that I now work with at UCL and we did it to generate pilot data for a very big experiment, a clinical trial that we're now running. So it wasn't just

one one-off sort of completely madcap thing it's an 80 ultra processed diet which is a very typical diet for a teenager in this country very typical diet one in one in five adults eats 80 of their calories so i had a washout period for six weeks and then i just ate what i wanted but with 80 of my calories coming from ultra processed food. And what happened? So I gained a huge amount of weight. In one month, I gained so much weight that if I'd continued for the whole year, I would have doubled my body weight. But there were two other kind of main effects that were surprising.

One was the satiety hormone effects. So we saw that in just a month, my response to eating a large meal completely changed that i could say that i didn't feel hungry and obviously that would be great to write in a book but you can't fake your blood hormone levels so a big meal didn't generate the same hormonal response as it had previously and the other thing i had was an mri and i don't know what tim would have said if i'd asked him a couple of years ago, but I thought we're not going to see any MRI changes on a brain scan stand up at four week intervals with a diet that's completely normal. And we saw very, very significant changes in the

connectivity between the reward addiction bits of my brain and the habit bits of my brain. Wow. In four weeks, your brain literally was rewiring. And we did it, the neuroscientists at Queen Square. So we weren't, we're not doing this in an amateur way. We're doing this with a big team at Queen Square of people who do functional MRI imaging. And we did it six weeks later because they were so surprised

and that the changes had stayed the same. So if this is happening to a man in their early 40s doing this for one month, and I previously ate about 30% UPF, what is this doing to children who possibly from birth are eating 80, 90% UPF for the first two decades of their life? Well, that's terrifying. So I would love to talk, you know, at the end here about what people can do. So could food manufacturers start making ultra processed food that was healthy? And what can listeners do listening to this and say, okay, that's all very scary. What are the practical things that I could do that would really improve my health?

So the first question, can food manufacturers sort of hyper process the food to make it more healthy? One of the things we know about UPF is it's soft and it's energy dense. And we know that those two qualities of the food mean that you consume calories quicker than essentially your hormone response can keep up and make you feel full. Now we've known about soft energy dense food since the 1990s. If the food industry could make the food chewier, less energy dense, and it would still sell as well, they would have done it by now because they could make an incredible health claim. The reason the food is soft and energy dense, it's not an accident of the processing. It's because that's the food that

sells incredibly well. Similarly, artificial sweetness, similarly, all the gums replacing fats. We've been hyper-processing already ultra-processed food now for, you know, since the early eighties, we've been replacing fats with, with cornstarch and gums. So I am very pessimistic that they can, they can further modify this food. To be honest, I don't think reformulation is going to work. And to some extent, why should we do that? We know the food, we have very robust data that the food that is associated with weight loss and with health benefits across the spectrum, it exists. You don't need to go and invent it. It's out there.

It's just terribly expensive and inaccessible for people. So instead of focusing our energies on reformulation, we should be thinking what is wrong with our world that people with low incomes are unable to afford real food. Yeah, I agree with all that. And there was a good example of, I spoke to a beer manufacturer who added fiber to beer, thought it was a great idea that actually you could have a healthy beer. And well, don't laugh, there are worse things. So beer is relatively only mildly processed. So add a bit of fiber to it. Okay. This would be healthy. It turned out people drank less

once they had it, so they had to abandon it. Oh, because it left them feeling full? They had 10% less than they would have the other beer. So even if they charged a premium, they were going to lose it. So this is exactly what you were talking about. There's a disincentive to health for the companies to actually improve them. So if I'm a consumer then, so then I'm thinking like the manufacturers aren't going to solve this for me is what you're saying. No, the government could. They could say, we want some minimum standards here, but they won't because the lobbying and the corruption in government is not going to happen anytime soon. And they want to keep the prices low because they worry about people rebelling and the nanny state,

et cetera. So you're not going to change that very easily. But I think for the consumer, the consumer should demand at least there is proper food labeling and there are warnings. We know these foods now are unhealthy. So let's not allow them to have health benefit stickers on there saying source of fiber and source of protein and source of vitamin C when we know that's nonsense. They shouldn't be allowed that. They should have health warning stickers saying this food contains ingredients that are not healthy for you and will make you overeat. Nothing wrong with that. And that's why in a way I'm happier for people to drink Coca-Cola

than orange juice. Because at least when you're drinking Coca-Cola, you know it's not Coca-Cola. You know what you're getting. You know what you're getting. Orange juice, it comes with various things about fiber and vitamin C that to have all these benefits and part of your five a day and all this sort of nonsense that you see. But the consumer needs to understand these foods and really books like Chris's make people understand what we are eating and what real food looks like and doing more cooking and having more things available. And we need to start in our institutions, in our schools, in our hospitals. We need to just say no to this epidemic of ultra processed food, which is killing us. But when I was, when I was on my diet, I had this incredibly powerful experience where I spoke

to some scientists in Brazil and they just kept underlining all the things the food was doing to me. And I sat down that evening to eat some fried chicken wings and I could not eat them. And so my invitation to people in the book is eat along with me. It's a bit, I mean, it's very, it's unashamedly like the quit smoking book where you smoke while you read, which is a very well evidenced book. There's loads of research on it and it's a World Health Organization endorsed book. So my invitation is do the experiment. You're already being experimented on. We've all, the food companies are doing the experiment to us, eat along.

And most people find as they eat the food, they start realizing the lies the food is telling them and it becomes disgusting. That's an individual solution. The solutions for government, exactly as Tim is saying, we know we need to think about labeling. I would say the number one thing to do is to put it in the national nutrition guidance, is to say ultra processed food is associated with health harms. Once it's in our guidance, we can all point to it and legislation can follow and everyone will know. And six countries have done that already. But as usual,

the UK is dragging its feet because of the food lobby. But, you know, you've already got most of the South American countries, you've got Israel, France, France now. Canada will,

even the States might. But yeah, we're again in the UK lagging so far behind. It's a political issue. I want to ask one final question here, which is because a lot of this, I think, is about what government might do. And so as an individual, there's a limit about what you can influence. Let's say you're listening to this. One option is obviously read the book and overdose on ultra processed food and give up. But let's say you're listening to this. One option is obviously read the book and overdose on ultra processed food and give up. But let's say you're just listening to like, you know what, I would like to cut down, but I'd like some guidance. Like where should I be? Where should

I start today if I'm listening to this? And I'd really like to get to this like low level of ultra processed. What would you advise someone who's listening to this right now for sort of practical advice? Well, start with breakfast because everyone is generally in charge of their breakfast. You may not be in when you go to work or you're traveling, whatever. Most people start the day and they've got choices. They can skip breakfast as some people do and just have a tea or a coffee, or they can say, I'm not going to have any breakfast cereal, 95% of which are ultra-processed. That would be a reasonable start. Don't have supermarket bread because that's also ultra-processed.

Don't have yogurt with anything added to it that isn't totally pure. And just by those, that would probably reduce your level of ultra processing by about a third. I love that idea that lunch, if I'm in the hospital and I want to eat a meal for lunch, it is impossible to not have an ultra processed meal. I can go to the fast food restaurants. I can go to the hospital canteen. It's all ultra processed. But breakfast, you're right.

Normally at home, most of us have breakfast at home. We can read the ingredients list. We know what we're buying i love that yeah so it's a good start but you know and the rest and take your own food into work i think that's the other thing and you see you know having worked in other countries it's much more common for people to take last night's meal in a little container and that's their lunch for the next day they know exactly what they're eating they're not relying on some third party night's meal in a little container and that's their lunch for the next day. They know exactly what they're eating. They're not relying on some third party to feed them in a healthy way, which we know we're going to be tricked in this country. So I think it's just changing some habits and not buying these snacks and these other things that we've become so dependent on just because we think they look natural and tasty or they've been around for 20

years. And I think fastidiously read your ingredients lists. Once you're into the idea, you have to look at the ingredients. You just start seeing all these things there and you start asking why your mono and diacetyl tartaric acid esters of fatty, of mono and diglycerides, the data and why the emulsifiers are in there. Why are the preservatives in there? What is oligofructose? And just asking those questions starts to make the food a bit weirder and less palatable. Why is there mango kernel fat in my biscuit? Not that mango kernel fat is per se necessarily harmful, but it should force you to ask a question about what the purpose of that biscuit is. The purpose is not to nourish you. The purpose is to extract money from you and to commodify your ill health.

I think that this is one of the most shocking areas that we've been discussing in the podcast. And partly that's also because I know when I first met Tim, which was about six years ago, he didn't talk very much about ultra-processed food. He was talking enormously about the microbiome and about like real food. But what I've noticed is that it's something that, Tim, you are talking a lot more about.

And so I think that shows you sort of the way in which the science is moving fast and the focus on the ultra processing rather than just like not having fiber. Is that, am I? has suddenly become the crucial factor. And it's only because of this recent science that's overcome all the pressure of the food industry, which is designed to make us not look in that direction and steer us away from that with all their labels and added vitamins and stuff like this,

or the smoke screen. It's only now that we're able to see exactly what's happening. It's only now, really, we've had a chance to take action against it and educate people. So it really is a very topical subject. We've been dancing around the edges thinking there's something not quite right here about all this stuff, but we haven't really been able to put a finger on it. Now we absolutely can and we can do something about it. And can I ask one final question?

Because Tim, you said right back in the quickfire questions, can you undo the damage from ultra-processed food if you stop eating it? And you said, you thought, yes. What would you be saying? Because there'll be a lot of people listening to this who are a bit scared now. They'll feel like, well, that's basically

what I've been eating for a long time. Is there any, you know, am I stuck? Is it all too late? It's not too late. I think everyone can improve their health. I'm particularly looking at it from the angle of the gut microbiome, which I think is key to our long-term health, and re-educating those guys how to eat real food again. For people who've been on ultra-processed foods diets, they've had abnormal microbes

because of the sweeteners, the emulsifiers, the preservatives, all these other chemicals in there, giving off the wrong signal. So there's still time to re-educate your gut microbes, feed them real plants, get them diversity, get them eating fermented foods, eat the rainbow, and stop snacking. All these things will improve your gut microbes, which will improve your health and counteract those years of ultra-processed foods. We don't yet know how much you can regain, but we do know it can improve. And I know some examples with my son who had his intensive ultra-processed food diet. He still hasn't recovered, but he's still better than where

he was. And so I think we should be optimistic and say, get our gut microbes back on track, feed them the right things, and our health will follow. And hopefully most people will benefit. Will my hair grow back? Absolutely not. Sorry about that. Well, it depends what you put on it.

You were meant to say you've got a full head of hair, Chris. That was the correct answer. I think that is a beautiful point at which to wrap up. I'm going to try and summarize. We've gone in a lot of different directions. And I also think it's clearly a topic we're going to come back to, I think, on a number of occasions, because you can see how much this is brand new science when you're both talking about these papers that are just in the last couple of years. But I think we start off by saying people are eating a lot more of these ultra processed foods than they realize, you know, more than half of all the calories in the US and the UK. But people are often thinking they're eating a lot less because often these ultra processed foods are sort of hidden. You know, you can see it in the

ingredients, but you just wouldn't be able to tell that there's some very complicated scientific definitions of ultra processed food, but fundamentally, does it contain things you wouldn't have in your kitchen that are therefore somehow like chemically produced in order to achieve something for the properties of the food? So it's not processing itself that's bad. We've been doing that for as long as we've had fire, but we're doing something very different in the last 50, 70 years that there's really good evidence that this is impacting our health now. And that's not just because you're eating more calories.

It's not just because of sugar or fat. Actually, the ultra processed food itself seems to be linked to it. Sounded like almost everything we don't like from dementia to depression to obesity. There's been some debate, it sounds like about whether it's truly addictive, but certainly in terms of the behavior that is driving. And I love Chris, your description of your experiment for yourself, like, it's really that your hunger hormones are falling. So you're just wanting more of this. So the net result is driving just much more consumption, yet again, showing that sort of this calorie counting thing doesn't really make sense because actually, you know, different calories affecting

what you then eat afterwards. I think you both basically believe there isn't a food manufacturing solution to this. We can't go to even more artificial food to make it healthy. We sort of got to reverse out of this because they're just taking away all these elements of the food that we're used to having and somehow they're just taking away all these elements of the food that we're used to having and somehow they're replacing it with all these things. We don't fully understand exactly the ways they're working, whether it's through the microbiome, whether it's through spikes and things, but somehow we have to get out of that. It sounds like it's not easy to

get out from where we are, right? You're saying this is a huge part of our food ecosystem, but at a minimum, we should be demanding really clear labeling. We should be saying that ultra processed food is bad. And that means that you would then start to have government guidelines against it. Pretty terrifying stuff about children where you were saying maybe 90 or a hundred percent of their food is ultra processed. And that's obviously, you know, we all worry so much about our children right and i think i love however a little bit of sunshine at the very end this was a slightly depressing podcast i think compared to some which is maybe think about ways you could take we'll start with breakfast you know think about swapping out if you're eating breakfast cereal actually you might think you're doing something really healthy and you'll look at it and you'll be like wow so

think about swapping that for stuff that isn't ultra processed. So bread with only ingredients you would have in your kitchen, yogurt, these sorts of things, taking food to work. So again, you know that you've got food that you can eat instead of most of us living in environments where it's very difficult not to. And I think the final thing, which for me has been the most shocking is just turn the food around and read the ingredients list and suddenly realize that many of the things you thought you were doing really well, you were maybe actually spending money on these things because you thought they were good for you and realizing that actually they were ultra processed. That's an amazing summary. He's good at this, isn't he? I try and pay attention, but thank you.

I wanted to interject, but you hit every point i think this is like a communication lesson my publicist is listening out there i'll do it i'll do that eddie wonderful i i really enjoyed that thank you both very very much likewise that was so interesting thanks thanks for having me on i really really enjoyed that it's always good i learn i learn a lot coming on this thank you chris and, for joining me on Zoe's Science and Nutrition Today. If based on today's conversation, you're interested in understanding exactly which foods in your diet are ultra-processed and find replacements with foods personalized for you, then you may want to become a member of Zoe and get advice to reduce your risk of chronic health

conditions. Your Zoe membership comes with the Zoe app, where you can score millions of foods and meals to find out how good they are for you. You also get personalized meal and recipe recommendations based on the results of your at-home test and access to our nutrition coaches who provide scientifically backed nutrition advice on how to eat for your best health. If you're interested in learning more, head to joinzoe.com slash podcast to get 10% off your purchase. As always, I'm your host, Jonathan Wolfe. Zoe Science and Nutrition is produced by Yela Hewins-Martin, Richard Willen and Alex Jones here at Zoe. See you next time.