The science behind food that isn’t food, why you love it and why you should not fear it all | Prof Tim Spector & Prof Sarah Berry

Are some of your "healthy" foods actually high-risk ultra-processed foods? For decades, nutrition advice seemed relatively straightforward. Eat less sugar. Less salt. Less saturated fat. Then it all fell apart. In today’s episode, we examine the research that has forced us to rethink what makes food harmful in the first place. Two of the world’s leading nutrition scientists, Professor Tim Spector and Professor Sarah Berry, tell their own story of why they’ve changed their minds about it. We explore why sugar, salt and fat aren’t the whole story, explain why ultra-processed foods are making us sick, and share groundbreaking insight that only a small portion of them are really harmful. By the end of the episode, you’ll know what to watch out for and what to worry less about when you’re food shopping. Next time you reach for a "healthy" yogurt or a quick pasta sauce, would you still choose it if you knew exactly how it was made? 🌱 Try our science-backed and tasty wholefood supplement Daily30 🌿Let your gut microbes snack on the ZOE Gut Health Bar Build healthy habits. Download the ZOE app today and start your trial for just £2.30 for your first week. 👉 Join ZOE Follow ZOE on Instagram. Timecodes 00:00 Intro 02:24 The biggest myth about spotting ultra-processed food 07:52 How much of your diet is actually ultra-processed 12:09 Why people ate 500 more calories on ultra-processed food 13:47 The study that changed how scientists see ultra-processed food 17:52 The hidden artificial sweeteners nobody noticed they were eating 20:29 What sweeteners did to mice in this gut bacteria experiment 23:57 What emulsifiers might be doing to your gut lining 28:27 Why food additive combinations are impossible to track 31:30 Can food texture alone change how much you eat? 33:08 Two ultra-processed diets, 369 calories apart 37:10 How the tobacco industry invented food's "bliss point" 39:33 Why hyperpalatable food makes you eat the whole bag 42:17 Does skipping cakes and soda avoid ultra-processed food? 46:38 The "ultra-processed" foods that are actually protective 48:32 How ZOE built its own ultra-processed food risk score 51:01 Why 72 calories a minute is one sign of a risky food 53:48 The 25% of ultra-processed food causing most of the harm 56:11 The one-question test for spotting ultra-processed food 59:32 ZOE says 25% of food is high risk, not NOVA's 60% 01:01:54 Why some "healthy" yogurts are full of hidden sweeteners 01:03:16 Why children's food is designed to make kids overeat 01:05:41 Two pestos, one full of hidden sweeteners 01:10:20 Ultra-processed food uses the same trick as cigarettes 01:11:41 Why you shouldn't fear all processed food 📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati The Appetite Reset by Dr Federica Amati Food For Life by Prof. Tim Spector Ferment by Prof. Tim Spector Good Mood Food (preorder) by Prof. Tim Spector Free resources from ZOE The Smart Snacking Guide: How to feed your gut, fuel your day, and snack without guilt The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra Eating for Better Brain Health: Your brain-gut blueprint How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks Better Breakfast Guide Mentioned in today's episode Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain, Cell (2019) Personalized microbiome-driven effects of sweeteners, Cell (2022) Food Emulsifiers and Metabolic Syndrome: The Role of the Gut Microbiota, Foods (2022) NutriNet-Santé Study Eating rate has sustained effects on energy intake from ultraprocessed diets, The American Journal of Clinical Nutrition (2026) The role of hyper-palatable foods in energy intake, Eating Behaviours (2025) ZOE’s PREDICT studies: What we’ve learned Episode transcripts are available here.

• 0:02Speaker 00

  Welcome to Zoe, Science and Nutrition, where world-leading scientists explain how their research can improve your health.

• 0:13Speaker 00

  For decades, nutrition health advice seemed relatively straightforward. Eat less sugar, less salt, less saturated fat. The advice was simple. If you were putting on weight and feeling unhealthy, the problem was your willpower, not the advice. Then it all fell apart. Over the last five years, a series of groundbreaking studies has shaken the foundations of nutrition science. Research from some of the world's leading institutions has forced scientists to rethink what makes food harmful in the first place. And at the centre of that scientific revolution is a controversial new idea: ultra-processed foods. A property of the food that does not show up in the macronutrients on the label.

• 0:56Speaker 00

  What's remarkable is that many of the leading researchers weren't always convinced that ultra-processed food was a real thing. As new evidence emerged, they had to change their minds.

• 1:08Speaker 00

  But today, I'm joined by two of those researchers, telling their own story of how they radically rethought nutrition science. Tim Spector, Professor of Epidemiology at King's College London and scientific co-founder at Zoe, and Sarah Berry, Professor of Nutrition at King's College London and Chief Scientist at Zoe. Together, they explain in simple terms the four breakthrough studies that transformed how they think about ultra-processed foods, our new understanding of why it is that ultra-processed foods are making us sick, and the brand-new insight that only a small portion of these foods are really harmful. We'll wrap up with brand-new research that helps to identify the specific ultra-processed foods that are making us sick, and those which we don't really need to worry about.

• 1:53Speaker 00

  Tim, have you changed your mind about the importance of ultra-processed food?

• 1:58Speaker 01

  Yes.

• 2:00Speaker 00

  Can some food additives cause gut inflammation?

• 2:04Speaker 01

  Yes.

• 2:05Speaker 00

  Sarah, are all food additives dangerous for our health?

• 2:10Speaker 02

  No.

• 2:11Speaker 00

  Tim, is it just the additives that make ultra-processed food bad for us?

• 2:17Speaker 01

  No, it's not.

• 2:19Speaker 00

  And Sarah, is it easy to tell how unhealthy a product is just by looking at its packaging?

• 2:25Speaker 02

  Absolutely not.

• 2:27Speaker 00

  And finally, Tim, what's the biggest misunderstanding that people have about UPF?

• 2:33Speaker 01

  I think it's that it's easy to tell if a food is UPF or not, and that's what the food companies hide behind, and they're very good at disguising what's in their products.

• 2:46Speaker 00

  Everyone listening to this knows that eating foods that are high in sugar and fat and salt is bad for them. They might be yummy, you might decide to have it, but there's no confusion. No one talked about ultra-processed foods when we started Zoe. But in the last five years or so, there's really been an earthquake in nutrition science, and ultra-processed foods, or UPFs as they're often known, is really at the centre of that controversy. And so today, I'm really excited, we're going to try and do something completely new on the podcast. I am joined by two of the world's leading nutritional scientists, my co-founder at Zoe, Professor Tim Spector, and our Chief Scientist, Professor Sarah Berry. And they are going to explain to us why they've changed their minds about ultra-processed

• 3:31Speaker 00

  food by talking us through four critical science papers that have really been the cause of this revolution in nutrition science, and this revolution about ultra-processed food. And then, for the first time, we're going to talk in detail about Zoe's own research on UPF and the actionable steps all of us can take to look after our own health and the health of our family.

• 3:55Speaker 00

  Before we jump into the first paper, Tim, can I confirm that when I first met you and we started Zoe, you didn't seem particularly concerned about ultra-processed foods? Is that true?

• 4:07Speaker 01

  Yes, I mean, it's not quite as black and white as that, because I knew about animal experiments, for example, where they'd looked at the gut microbiomes of mice being fed burgers and junk foods and seeing this effect on them. But there were no clinical data at all to compare with that, and so I'm always wary about anything that's just in mice or in animals. I knew there was building evidence, and the microbiome might well have been, you know, one of the ways we could learn more about it, but there just wasn't a way of studying it.

• 4:46Speaker 00

  So what changed?

• 4:48Speaker 01

  There was a definition of ultra-processed food which appeared in the epidemiology literature, which took a while to get going, but about 10 years ago started to be used by researchers, which allowed us to study it in the first place, because before then you really couldn't do it outside an animal laboratory. And the other thing was there were some key studies started to be done, and the results of these have really been major breakthroughs in nutrition science that before just weren't around. People just didn't think about it until these studies were done.

• 5:29Speaker 00

  And these papers, and I know you've selected for today, these are the papers that have really changed your mind about how important this is versus other things like, you know, the number of plants and all the rest of it?

• 5:39Speaker 01

  These papers were crucial to me changing my mind about the dangers of UPF, because they showed us the mechanisms. It was all very well to say these are dangerous, but you never really knew if it was just due to the fats and the sugars and the things that are obvious. I hadn't really separated that. So these really careful studies have separated out these mechanisms and given us a real pathway about why these foods might be bad for us, as well as how bad they are for us.

• 6:07Speaker 00

  And Sarah, who first came up with the concept of ultra-processed food, and how were these UPFs defined in those early days?

• 6:15Speaker 02

  So there's a classification system called the NOVA classification system, and this classified foods across four different levels. And it's NOVA4, which is the level that's considered ultra-processed. And this classification system is based on the extent of processing and also the purpose of processing. And this is the classification system that's typically used to classify food as ultra-processed. There's a slight problem with it, that it is very broad, it's very vague, so it's very difficult to actually identify yourself if a food is what we call the NOVA4 classification. And this classification system, and this is really important, was specifically built

• 6:56Speaker 02

  on the purpose and extent, but never took into account the actual health effects of the processing.

• 7:03Speaker 01

  It was also designed by epidemiologists so that it could be used across the world, across very different food systems, to give you results that could be useful when you combine them. So it's very much at the population level rather than at the individual level, and I think that's really important for people to realise.

• 7:20Speaker 00

  So having come up with this idea of ultra-processed foods, you know, just a decade ago, how common are these UPFs in our diet in the UK and the US?

• 7:31Speaker 02

  So UPF, according to the NOVA classification, accounts for about 55% of the calories that we consume in both the UK and the US for adults. What I think is more worrying is that it accounts for about 65% of the calories that adolescents and children consume.

• 7:48Speaker 01

  And that's even, I think, by some surveys, greater in the UK than the US.

• 7:54Speaker 00

  And so, is eating a lot of these ultra-processed foods linked to poorer health, Tim?

• 7:59Speaker 01

  Undoubtedly, yes. There's numerous studies showing this is the case, at least 20 population studies around the world. They all show, in observational epidemiology, a clear association between eating of these foods and co-existent chronic diseases. So you name it, it's associated with everything from mental health to cancer, heart disease, diabetes. You get increased rates the more UPFs are in your diet. And some studies have adjusted for things like saturated fat and sugars that we know

• 8:40Speaker 01

  are bad for you, and they still see an effect of what we assume is what's rest, i.e. the processing and the way those foods are made.

• 8:49Speaker 00

  And Sarah, you know, when I listen to this, I'm thinking, isn't this exactly the same as what I was told as a kid, like, don't eat lots of junk food because it's high in fat and sugar and salt. And so this, you know, this NOVA classification of UPF, how's that different from just saying, don't eat junk food that's got all of this sugar and stuff in it?

• 9:09Speaker 02

  We know that food contains thousands of different chemicals, some of which are added by the food industry, like the additives, emulsifiers, et cetera. But we also know that processing can change the structure and the form and the texture of the food. So we need to stop thinking of food just in terms of the nutrients, just in terms of how much salt, saturated fat, you know, sugar, for example, there is. And we need to think of the bigger picture, the form of the food as well.

• 9:35Speaker 00

  And so is that the big shift? It's going from saying, like, what makes this food bad for me is like the thing that just classically, obviously on the label, you know, 30 grams of sugar or, you know, 15 grams of saturated fat, to like this much more complex thing where they've sort of changed the processing of the food, but maybe those ingredient numbers still say, you know, 15 grams?

• 9:59Speaker 02

  Yeah, absolutely. So I would say like 50 years ago, the backpack labelling was highly relevant. And yes, obviously, the amount of saturated fat, sugar is important. But the food landscape now and the food that's on our shelves has been changed so much that I think that that backpack labelling is less relevant. It still has some relevance. And we know from my own research, for example, you can have two foods that can have exactly the same backpack labelling. But because of the way that their structure has been changed, for example, through processing, can have entirely different effects on the body. So that's why we need to think beyond just the backpack labelling.

• 10:35Speaker 00

  I would love now to talk about the four papers that you've sort of picked out that have led you also, I think, to really change your, your views and say, well, actually isn't just the, the fat and, and the sugars. So Sarah, what is the first study that you'd like to talk about? I'll never forget the moment that everything shifted for me. I was at a public talk on nutrition, listening to a speaker explain that my gut had trillions of microbes in it, and that these bugs shaped every aspect of my health. That speaker was Professor Tim Spector, one of the world's top 100 scientists, who became my co-founder here at Zoe. Nine years later, Zoe runs the world's largest gut health research study. And the conclusion

• 11:16Speaker 00

  is simple. Gut health is health. How you feel, your long-term health and your digestion are all shaped by the state of your gut. As a listener to this show, you know how important it is to feed your good gut bugs. But I suspect that like me, you have a busy schedule. And often you feel you haven't given them all the different plants they crave. And that's exactly why we created Daily 30. It's a gut health supplement packed with over 30 plants that you sprinkle onto any meal. It tastes great, adds a satisfying crunch, and gives your gut the diversity it craves. Finally, a healthy, happy, that's easy to stick to. I should note, I take it every day. And because we're Zoe, we don't just guess, we test.

• 11:58Speaker 00

  We put our original Daily 30 formula through a randomized controlled trial, the gold standard of testing. The results blew us away and proved it supports your digestion, energy and gut health. That trial helped us develop the formula we have today. Today, Daily 30 is a non-negotiable daily habit for me. So don't put your health off for the future. Go to Zoe.com/daily30 and try it today.

• 12:23Speaker 02

  So the first study is a study that was conducted by Kevin Hall in the US. And it's a study that I think is really important because it shows, for the first time, the causality. It's a randomized controlled trial, which is like the gold standard in terms of research. And it proves for the first time that there is something actually going on due to a food being processed. And in this study, he fed 20 people either a ultra-processed food diet, according to this NOVA classification, or he fed them a minimally processed food diet. It's what we call a crossover study. So people followed for two weeks, one of those diets, and then they crossed over and followed the other diet. So every individual

• 13:06Speaker 02

  had two weeks on either a minimally processed or an ultra-processed food diet. And what he found was that each day, people were consuming a vastly different amount of calories. So they were consuming 500 calories more per day when they were on the ultra-processed food diet.

• 13:25Speaker 00

  500 calories more each day?

• 13:27Speaker 02

  Each day. They had on both diets, similar amounts of fibre, similar amounts of fat, similar amounts of sugar, salt, carbohydrate. So they were nutritionally matched, but they were different in terms of their processing.

• 13:42Speaker 01

  One just has the ingredients you'd find in your kitchen, the other one has all the tricks of a food company with the preservatives, the additives, the sweeteners, the colorants, et cetera. And that was the basic difference, but they were made sure that the amounts of the macronutrients, the fats, the calories, et cetera, were identical.

• 14:02Speaker 02

  This was a very well conducted study. It was done in what we call a metabolic ward setting. So basically, Kevin had these participants in his metabolic unit. They lived there for two weeks. And they were given as much food as they wanted on each of the diets, so that they were in that kind of what we call free living setting where they could eat until they were full. I think what was also interesting, as well as this big difference that they saw every day of 500 calories, what they saw in as little as two weeks was actually a difference in weight loss as well and weight gain. So people who were following the ultra-processed food diet gained nearly a kilogram in just two weeks.

• 14:44Speaker 00

  Gained a kilogram, so that's two pounds in two weeks?

• 14:47Speaker 02

  Yes.

• 14:47Speaker 00

  On the UPF?

• 14:48Speaker 02

  Yes. And on the minimally processed diet, they actually lost nearly a kilogram of weight. So there was like this two kilogram weight difference between those two.

• 14:57Speaker 01

  For us in the field, it was a real game changer because suddenly, we're moving from, okay, these additives might cause cancer or have some other effects or, you know, make kids go crazy. But no one had actually thought that the processing could lead to this overeating and obesity, you know, and obesity, just by the fact of how they've done it.

• 15:20Speaker 02

  And I think as well, what I found really interesting as a nutrition scientist is they started to also be able to tease apart some of the mechanisms that were going on. You know, when we think about ultra-processed foods, we typically thought about, oh, the additives, the emulsifiers, that's causing some sort of issues. But they looked at factors like eating rate. And what they found in this study is people were consuming calories 50% more quickly on the ultra-processed food diet compared to the minimally processed. So they're eating their food really, really fast. And that's likely because the structure of the food is broken down during processing, the texture of the food is very different. So we know that people in our Zoe cohort who consume food more quickly, on average,

• 16:04Speaker 02

  consume 120 more calories a day. We know that if you slow down the rate that you eat your food, that you will consume less calories. So this processed food diet that Kevin Hall was feeding had a kind of texture, for example, that meant people were eating their foods very quickly. And that's likely one of the mechanisms why we're seeing this 500 calorie difference. And I think that's what's really fascinating. It's the first study as well, starting to move beyond, again, this reductionist view of food processing, that it's about the additives.

• 16:33Speaker 00

  I'm listening to this and saying, well, that paper sounds so great. Why do you even want to talk about three more papers? Doesn't that solve everything?

• 16:40Speaker 02

  Food's complicated, Jonathan. I've told you that so many times. That was, I think, the first randomized control trial that shows, okay, there is some causal effect happening here. It's not just an association. There's something happening independent to the nutrients. There's something happening to the speed, the way we eat our food. But that only tells us, again, one piece of a very, very complex puzzle. So much changes when we process foods, not just the nutrients, not just the chemicals, but so many other things. And so, yes, that's interesting. But obviously, as scientists, we need to go further.

• 17:16Speaker 00

  And so, Tim, I think you have a second study that you wanted to talk about.

• 17:20Speaker 01

  Yes. So that eating study didn't address this whole question of the additives. And there've been mouse studies and showing that these various additives could affect mice and make them, you know, get diabetes and, and other things. But there hadn't been any human studies of any size at all. And people particularly interested in artificial sweeteners. And so this very good Israeli group from the Elenav Lab at the Weizmann Institute had been doing some of these studies in, in mice and then got a grant to do a big, big

• 18:02Speaker 01

  study in humans to see what were the effect of various artificial sweeteners on the gut microbiome and health. And so what these guys did was to say, let's recruit 120 normal people who have very low exposure to artificial sweeteners, and let's test them with four of the common ones, and see what happens to their gut microbes, and then see if that is gonna... Have an effect on their blood parameters of metabolism, et cetera.

• 18:44Speaker 02

  I actually had a conversation with one of the study authors. And they said that the most challenging thing, which we know whenever we're doing studies is recruiting our participants. But they found it even more challenging for this study because they needed people that weren't previously exposed or consuming many sweeteners. And so there were lots of people that said, oh, yeah, I don't consume sweeteners. But actually, when they went and did a diet history check, they realised that these people were consuming sweeteners. And the reason there was this misunderstanding is because sweeteners are actually hidden in so many foods that we don't even realise. So typically, I think we thought of sweeteners as in, you know, you add a sweetener to your cup of tea.

• 19:24Speaker 02

  Or we know that maybe a diet drink has sweetness in it, but they're hidden in so many foods.

• 19:30Speaker 00

  Could you give an example for somebody listening to this who says, well, I definitely not eating any sweeteners, where might they be hidden?

• 19:36Speaker 01

  You might have a sports drink, for example. Electrolyte, rehydrate your body type thing that would have sweetness in it.

• 19:44Speaker 02

  Yogurt.

• 19:45Speaker 01

  Low sugar, low calorie foods usually have sweetness in them. Some ready-made sauces have them, some in ready meals.

• 19:55Speaker 00

  So like my pesto or my meatball sauce could actually have sweeteners in it?

• 20:01Speaker 01

  Yes.

• 20:01Speaker 00

  So they found it really hard to find these people who weren't having sweeteners. But you said after two years, they finally found one hundred and twenty people who weren't taking them. What happened?

• 20:12Speaker 01

  Then they tested these four common sweeteners and found that two of them had a marked impact on the way they handled blood sugar. So their glucose levels were altered so that the insulin wasn't working as well as in the other one. So of the four sweeteners, they found the two very common ones, saccharin and sucralose, which are in many products, blunted the glucose response. So this is the response that when your blood sugar goes up, your insulin gets triggered to get the sugar levels down. So this meant that the glucose was hanging around longer in your body when they did a formal test.

• 20:55Speaker 01

  So everybody in this study had these formal glucose tolerance tests, we call it, which just stress the system. So that was a major finding, essentially having these two products could over time lead to an increased risk of diabetes. The other finding was that all four of them, and the other two were aspartame and stevia, which find in many sodas and drinks. So all four of them affected the gut microbiome and caused what we call a dysbiosis. So they shifted the gut microbes in ways they think were broadly negative.

• 21:39Speaker 01

  And then when they did another experiment is they transplanted the poo samples from individuals that had the biggest negative effect of the sweetness on their gut microbes into sterile mice. And those mice then developed diabetes type problems. So it's a bit of a complicated story, but what it's saying is that two things, there are definitely some sweeteners that straight away cause problems with your glucose metabolism. All of them to some extent cause a distortion of your gut microbes. Not everyone reacts the same.

• 22:23Speaker 01

  So it was only, you know, a quarter of them that had a big change. Some people didn't change at all. And those people that do change, they're clearly getting these metabolic disruptions from these sweetness. So it is telling us that all of them potentially can be doing harm, but we're all going to react to them differently. And I think that's it's this idea that there's a personalised effect of these sweeteners on us. And that's why it's even more complicated because nowadays the food manufacturers put multiple sweeteners into the same product. So very hard to avoid one because it's nearly everywhere in small amounts.

• 23:08Speaker 02

  People generally, I think, think sweeteners are sweetener. I don't think people will think, oh, is it saccharin, is it sucralose, is it A C K, is it aspartame? These are four most common sweeteners, but they all have very different effects. And they have different effects because of the way they're metabolised. And I think that's what's really interesting. And I think, you know, there's studies now starting to look at how different additives and sweetness might even interact because we know that generally they're not found in isolation as well. And I think that's really important.

• 23:38Speaker 00

  So the thing that surprises me is maybe even simpler, which is I had understood that the whole thing about sweeteners was they tasted sweet in your mouth, but then they like had no effect on you. And that was why we were supposed to have a sweetener and not sugar. And so isn't it meant not to have any effect on your body? But it does sound, as I understand it, you're saying that even for the people where it didn't increase their risk of diabetes, it was actually changing their gut microbiome in a bad way?

• 24:09Speaker 01

  Yes, this study and a number of other studies have definitely shown that these substances are not inert. And that's what, you know, we were told, that these sweetness were inert and had a thousand times the potency of sugar. Therefore, you know, could would be a dream to guess, you know, less addicted to sugar. But it turns out that, you know, no such thing as a free lunch. And it turns out that we do pick up these chemicals and our bodies do react with them. And what we're seeing is they react in slightly unpredictable ways. And everyone might be reacting to one chemical and not to another.

• 24:52Speaker 01

  And that's why it's particularly worrying that we're now faced with a whole range of chemicals, all of which can influence the gut microbiome in some way, which we still don't know exactly whether it's good or bad or what it's doing. But it's definitely changing our gut microbes. And you know, apart from artificial sweeteners, nearly all of these foods have emulsifiers in them. And they stick the foods together, there are like twenty odd emulsifiers you commonly find in foods like carrageenan, like lecithin, like the gums, gua gums, et cetera. And there've been some careful studies showing that they affect the gut lining as well as the microbes.

• 25:33Speaker 01

  So we think they're, you know, causing problems for our microbes, making them stick together or altering the gut lining, which can cause leakiness. And so all these chemicals in some way have the potential to cause us problems. Not all of them do, and there might be some ones that are harmless. But at the same time, we know enough of them are problematic.

• 25:57Speaker 00

  And Sarah, are there any other additives other than these sweeteners and these emulsifiers that we need to watch out for as a result of all this, you know, scientific discovery?

• 26:07Speaker 02

  So you have your sweetness, you have your emulsifiers, like Tim said, that are put into foods to enable ingredients to mix together. So they're typically found in the kind of foods where you have a water and an oil. So if you think of a low fat spread, for example, you can't mix water and fat. I mean, we all know if you were to put some oil in a glass and then add some water, it separates. So this is why emulsifiers are used a lot. So they're found in lots of sauces like mayonnaises, other table sauces and low fat spreads. So there's this group of emulsifiers, like Tim said, they're not all equal in terms of how they impact our health.

• 26:47Speaker 02

  We still don't know everything about them, but there's some good emerging evidence to show that some detrimentally impact our microbiome. But there's others that would appear to be safe, like soy lecithin, which is actually one of the most common emulsifiers. It's an emulsifier that's found in like egg yolk, also found in soy, and that's typically used by most manufacturers. You also have colourants, so these are to change the colour of the food. Now you can have natural colourants and it's kind of a bit of a vague term just because it says natural colour. It doesn't mean it's necessarily good for us, but you can have natural colourants like beta carotene.

• 27:21Speaker 00

  Beta carotene does not sound like a natural colourant to me.

• 27:24Speaker 02

  Vitamin A.

• 27:25Speaker 01

  But if you could call beta carotene extract of carrot.

• 27:28Speaker 00

  Okay, so that comes from a carrot?

• 27:30Speaker 02

  Yes, yes.

• 27:30Speaker 00

  Okay.

• 27:31Speaker 02

  And so it gives the spread that nice yellow texture, so it looks like butter, you know, instead of kind of a more white texture that it would have naturally. Tumouric, these are our natural colourants. But then you have artificial colourants, you know, people often talk about the red dye, the blue dyes, you know, that we know that probably aren't so healthy for us.

• 27:49Speaker 00

  Other than this one study from Ellen Ave that you're talking about, I mean, is there any evidence that any of these other additives, other than these four sweeteners, have any negative impact on my health?

• 28:00Speaker 02

  So there's emerging evidence that some emulsifiers, not all emulsifiers, can negatively impact our gut microbiome. There is some evidence that some other additives, again, may also negatively impact our gut microbiome, may also negatively impact our metabolic health, so things like our insulin sensitivity. But it's very nuanced and it's different depending on the dose of the additive and the type of additive.

• 28:25Speaker 01

  There is some evidence about dyes as well. So I think the reason they've been taken off the list by the EU and more recently in the US is because there are, you know, quite a lot of certainly pre-clinical evidence that they are harmful and rather unnecessary. You know, just add colouring, why would you take a risk on a food if you're not sure? But I think there's one study from the really good French cohort that had looks at one hundred and eight thousand people, followed them for nearly eight years, called the Nutronet-Sante study, that has got very detailed food records and they looked and saw the, where there was a combination of these various additives in food that caused problems.

• 29:09Speaker 01

  And they were looking at five sort of networks that they.

• 29:15Speaker 01

  They looked at and two of these five were associated with a higher rate of type two diabetes. And they were classically this mixture of having emulsifiers, dyes, preservatives, gums and acidifiers. And there were these two, these two clusters that went with that. So to Sarah's point, it could well be that there is a certain mix that just gives you the right ingredients that is going to cause problems. And I think this is a fascinating but frightening prospect. You know, how's the consumer going to work that out? It's impossible.

• 29:53Speaker 00

  Do you have a friend or loved one who's trying to eat more healthily? Someone who's genuinely trying to make better choices, but can feel overwhelmed by conflicting advice? Why not send them this episode so they can understand what they should be doing when they go into the supermarket and have to choose what to eat? So are you guys saying that it's not necessary that this is like one or two additives that are really bad for you? It's that potentially we're being exposed to hundreds of these different additives and sort of the combinations are causing their own problems. And as we're having more of them, it's sort of like building up. But as a result of all of that, you know, our modern diet, these additives really are impacting our health?

• 30:35Speaker 01

  Yeah, I think so. I think there's no doubt that manufacturers are trying to confuse us with more and more ingredients of smaller amounts. And like the artificial sweeteners, you rarely get one artificial sweetener now. They're often in combinations, even with a tiny amount of sugar or giving it another name of sugar just to confuse you even more. So as we see these, these, these combinations, the chances of them having an effect probably are probably greater and very hard to avoid for the consumer.

• 31:04Speaker 02

  I think it's really important though, Jonathan, for people not to over worry in terms of some of the scaremongering that is out there around cancer, that it is very clear at normal intakes of all of these additives and emulsifiers, there's been very good studies that show that they do not lead to cancer. And I think that's the one thing that I'd worry about is that people suddenly become very frightened of the food they're eating.

• 31:31Speaker 01

  Well, I'd caveat your caveat, Sarah, if I could.

• 31:32Speaker 02

  You caveat my caveat, Tim, you always do.

• 31:34Speaker 01

  They've done short-term studies, yeah, often on animals showing high doses of these products don't lead to cancer, liver cancer in these animals. But they haven't done long-term human studies to rule out that possibility. But I think population studies and the meta-analyses suggest that safer cancer, they might be somewhere between a 20% increase and a 50% increase using very crude measures of ultra-processed food. I think it may be that when we get a better definition, it's higher, but it's not a massive increase. Nobody wants a 50% increase in cancer risk through a lifetime of eating ultra-processed

• 32:17Speaker 01

  food, but that's probably the levels we're looking at. It's not like a tenfold increase.

• 32:22Speaker 02

  But that's likely not to be necessarily a direct effects of additives on cancer risk.

• 32:29Speaker 01

  No.

• 32:30Speaker 02

  It's likely to be the fact that the more ultra-processed food you eat, the more calories you eat, as we've seen from our first study, the more likely you are to be overweight, the more likely you are to have metabolic disturbances. And we know that many cancers have increased risk if you are overweight, if you do have metabolic disturbances, if you are in a pro-inflammatory state.

• 32:49Speaker 00

  Well, that sounds like the perfect transition to the third study that you wanted to bring, Sarah. Can you tell us about that?

• 32:57Speaker 02

  Yes, this is one of my favourite studies. It was published only the end of last year. It's called the restructure study. And this is a study conducted by a scientist, Kieran Ford, based in the Netherlands. And he wanted to pick up on some of the findings from that first study that we talked about, the study by Kevin Hall, that showed that there were differences in calorie intake and differences in how fast people were eating the food, depending on whether the food was minimally or ultra-processed. And so he did a randomised control trial where he recruited 41 participants to follow for two weeks, a diet that was actually very ultra-processed. So about 95% of their calories were coming from ultra-processed foods.

• 33:41Speaker 02

  But what he wanted to do was to tease apart, what is the impact that the texture and eating rate has in terms of how many calories we're consuming? So he put all of these people on this highly-processed diet and then he modified the texture in one of the diets so that it would encourage you to eat the food really fast. So it was a very soft textured diet. The other diet was a hard textured diet, so encourages you to eat it quite slowly. The hard diet might be where your carrots are quite al dente, your pasta's quite al dente, you've got a crunch to your carrots versus the carrots are really cooked so that they're very soft and very easy to eat very quickly.

• 34:23Speaker 02

  So it's not just that you kind of liquidise one diet and the others in its original form. It's that you have that crunch, so you're chewing more. And so what happens is with that harder diet, you eat it more slowly. And what they found was, remember, these foods are all classed as ultra-processed. They found that the people who were having the hard textured ultra-processed diet consumed 369 calories less each day compared to those having the soft textured diet.

• 34:55Speaker 00

  Consumed 369 calories less, even though it's ultra-processed food, just because it's like really chewy?

• 35:00Speaker 02

  Yes. And when they looked at, did they achieve what they ultimately wanted to do, which is change the eating rate by changing the textures? They found there was about this 43% difference in the rate at which people were consuming the calories. So what that means is people consuming the ultra-processed food diet that was hard consumed their food a lot more slowly and therefore consumed a lot less calories. Conversely, those that were consuming the soft ultra-processed food diet were eating their food very quickly and therefore consuming 369 more calories a day. Now, if you look at this in terms of the build-up effect, over two weeks, that's a difference of about 5,000 calories.

• 35:41Speaker 02

  And that's just by changing the texture of a food, which is what typically happens when we process food.

• 35:47Speaker 01

  Yeah, and that's what the food manufacturers do when they make a ready meal. If you noticed, you know, your, your pasta is nice and soft and gooey and easy to eat it. It's like, you know, everything tastes like mashed potato.

• 36:00Speaker 00

  So can I ask a naive question? If I have a slower eating rate on the hard food, why don't I just eat for 43% more time and then I will just eat as many calories? It seems really weird that the fact it's a bit slower would change how much I eat.

• 36:18Speaker 02

  I think there's quite a few things going on here. So when you eat hard textured foods, you have to chew them more, don't you? So automatically that slows down how fast the different nutrients are entering your, your stomach. We also know that hard textured food tends to have more of their food structure intact. So what that can lead to is the food being absorbed lower down your gastrointestinal tract, lower down your gastrointestinal tract, you have a lot more of these fullness receptors. So you tend to feel fuller for longer. And so you've got the speed at which it's entering, you've got the fullness receptors changing how much they're kind of firing. And we do know it takes about 20 minutes for kind of that fullness signal to come back to your brain.

• 37:03Speaker 02

  So there's lots of different things going on, but I think what's fascinating here is whilst I'm bringing in all these complexities, that actually it's a really simple thing ultimately that's going on. Hard textured food causes you to slow down how fast you're eating it, as well as changing all these metabolic responses, and ultimately can reduce the amount of calories that you're consuming. Soft textured food, which many ultra-processed foods are, causes you to gobble up really quickly, changes your metabolic response, causes you to eat more of the food, more of the calories and can have long-term knock-on effects then.

• 37:38Speaker 00

  Tim, tell us about the fourth and final study.

• 37:40Speaker 01

  The final study to discuss is from Tara Fanzino's group in the US that have been studying this concept of hyper-palatable foods. And a hyper-palatable food is a food that's been deliberately produced to override our fullness signals and at the same time excite our reward centres. So changing that normal balance that we have between sort of fullness and reward.

• 38:17Speaker 01

  Sugar, salt, fat and carbohydrates are tweaked in the right proportions to produce what's called the bliss point. And this is what nutritional scientists have been working on since about the 1960s. And they first started working in the tobacco industry to do this for cigarettes, interestingly. So they started adding little bits of sugar and other ingredients to cigarettes to make them even more addictive. And the early processing companies were all, a lot of them were owned by the smoking industry. So this is what they do.

• 38:57Speaker 01

  And what this group tested was whether foods that contained this magic combination of the salts and the fats in these exact proportions, which have been worked out by these brilliant scientists, actually made a difference in real life. And they told 29 participants to basically take pictures of their food for four days using an app a bit like Zoe's, so that it would capture the foods and then they then analysed those foods and saw how many of them were what we call hyper-palatable by this definition. And it turned out that those people that were having hyper-palatable foods were overeating.

• 39:45Speaker 01

  Uh, by about uh, three hundred calories um, per day. More than the people who were having the non-hyperpalatable foods. And it didn't matter how hungry or not they were at the beginning. So it was independent of hunger levels. So these chemically produced magic mixtures, you know, that extra bit of salt and fat that they put into biscuits and things just made people eat more than their hunger levels were really suggesting they should do. And this was the first real life study testing this uh, theory that a key component of ultra-processed foods is this mixture of these common ingredients to produce this bliss point that

• 40:31Speaker 01

  just lights up our reward centers and dampens down our fullness centers.

• 40:36Speaker 02

  It's interesting, um, and it's showing the importance of that kind of bliss point um, and the overriding of our natural satiety signals. But for any scientists that will be listening, if they are, you know, we do, it's important to say it wasn't a randomized controlled trial. There wasn't a control group. But what we do know is that we now have so many foods that have this mix of nutrients that wouldn't be typically found in nature.

• 41:00Speaker 00

  So is this why I have no interest in eating lots of potatoes? And I have no interest, definitely have no interest in eating lots of oil, right? Oil is disgusting on its own. But when it all comes together into that potato chip or crisp, suddenly I eat the entire bag and immediately want a second one.

• 41:17Speaker 02

  Yep, because it's yummy.

• 41:18Speaker 01

  It's the carbs, it's the fat, and it's the salt. You put those three in the right combination, it's irresistible.

• 41:25Speaker 00

  I'd like to now start to talk about like, what does it actually mean for all of us? Because like, that's really interesting as scientists, but I think we all want to know what should it do about what we eat. The first question on my mind is, does any of this really matter? Surely if I just eat healthily and don't eat lots of junk food, I'm going to avoid all of this UPF, like I don't need to worry about it.

• 41:48Speaker 02

  Well, I think firstly, given that such a high proportion of our calories come from food that's classified as ultra-processed, you can't just avoid it. I think it's very difficult in the current food landscape, but more importantly, it's really, really difficult to spot what is a food that's been processed in such a way that it's unhealthy for you versus a food that is potentially healthy for you. And that is where I think the biggest challenge is. I've been a nutrition scientist for twenty five years. When I go into a supermarket and I'm trying to choose the right cereal for my children, even I'm not really sure what's the healthiest option, you know, and the less healthy option. And that might sound ridiculous, given my twenty five years of training. It's really difficult to know.

• 42:30Speaker 01

  In the UK at the moment, there's no guidelines that tell you to avoid ultra-processed food. They might say, avoid high-fat foods like burgers and pizza, but they wouldn't tell you anything more broadly that there's certain types of food with lots of processing you should avoid. The US has recently changed its guidelines to include uh, avoidance of ultra-processed food and highly sugary foods for kids. So most other countries are making moves in that direction, but they're not really telling you exactly what one is to do. So that, that's the problem that Sarah was saying. Even if you know that you should be avoiding ultra-processed foods, that sixty percent of our diet, that's going to be really tricky uh, for you to do that.

• 43:15Speaker 01

  And we haven't worked that out.

• 43:17Speaker 00

  And can I clarify this? So if I go into the supermarket and I just don't buy anything on you know, the sort of the cakes and the pastries, and I don't buy any of the sugary drinks.

• 43:32Speaker 00

  So all the things I would just think about, you know, my, my grandmother would have told me, well, you know, that's like junky food. Will I not have therefore avoided all the UPF that's in the supermarket?

• 43:44Speaker 01

  No, I think you've avoided maybe ten percent of it.

• 43:46Speaker 00

  Only ten percent?

• 43:47Speaker 01

  I think there's so much more in, in the foods that we have every day, things like breads, uh, things like yogurts, uh, most children's foods, breakfast cereals, uh, all these sauces, these cooking sauces, ready meals. All these things contain uh, a lot of these problems that we've been talking about that is going to make you hungrier and, and cause problems. And this is the obstacle we're faced with now is how do you sort out the non-obvious stuff?

• 44:19Speaker 02

  It is challenging to change our diet. And so if you are someone that's getting the majority of your foods from foods that have been processed, there's a big price differential as well, and it's really important we acknowledge that because it's very easy for us to sit here and say everyone should avoid any processed foods. There's about a fifty five percent price difference between a heavily processed versus minimally processed food within a food category. So for example, a heavily processed bread versus minimally processed or heavily processed yogurt versus minimally processed. That's a big price difference. So lots of people cannot afford in the supermarket to buy the minimally processed equivalent food. And I think it's important we acknowledge that.

• 45:00Speaker 00

  I'd like to move on now to like what you should do. Should we try and avoid the sixty to seventy percent of food in the supermarket that is classified as UPF under that NOVA classification that you talked about at the, at the beginning of the podcast?

• 45:17Speaker 02

  I don't think so, and I think there's some very clear epidemiological evidence um, and clinical trial evidence to show that not all ultra-processed foods using the NOVA classification are bad for you. So for example, if you start to tease apart the evidence, we see in totality, people consuming more ultra-processed foods defined by this NOVA classification, yes, have higher risk of all-cause mortality of many diseases. But actually, if you start to look at individual food groups, and this is really important, we see that there's certain groups that are driving that, the sugar-sweetened beverages and artificially sweetened beverages, the processed red meats and other meats.

• 45:56Speaker 02

  But what we see is there's actually a more protective effect, for example, of whole grains, even if they're classified to be ultra-processed using the NOVA classification, that actually they might be protective. So we can't just group them all together. But how a consumer identifies within then the whole grains, which is better or which is worse, is really, really difficult.

• 46:19Speaker 00

  So Tim, I know that you basically kicked off a big piece of research at Zoe, I guess, two years ago around this topic. Can you explain why and what you and Sarah wanted to try and solve?

• 46:33Speaker 01

  Yes, so we realized that ultra-processed food was a problem. We also realized that the, the current way of defining it, the NOVA classification, was also a problem for the consumer. It was good for broad research, it's done a great job so far, but I wanted something else to be able to tell people, use this definition in order to pick the sort of foods that aren't going to cause you problems, those that really need to avoid and those in the middle. And so uh, I said, we must be able to come up with a way at Zoe to be able to divide uh, foods based on this latest science in a way that the consumers can understand and that doesn't demonize all foods.

• 47:17Speaker 01

  And so that was basically the challenge. I said, we must be able to do a better job than NOVA. It can't be that hard to do this. And uh, that was a couple of years ago. And you were a little bit skeptical, weren't you, Sarah?

• 47:30Speaker 02

  I said, we absolutely can't do that. Food is so complicated, Tim, it's so nuanced. There's so many different features that processing impacts, whether it's the macronutrients, whereas, whether it's the other thousands of chemicals, whether it's the structure, the matrix, et cetera. There's no way we can capture that.

• 47:46Speaker 01

  I always knew that, that's what you always say, so I kept persisting. And eventually.

• 47:51Speaker 02

  We came up with a Zoe Processing Food Score.

• 47:53Speaker 01

  Yeah, you did it.

• 47:55Speaker 02

  So we developed a, a Processing Food Score that was based on what the latest evidence shows are the key features that processing impacts to impact our health.

• 48:06Speaker 00

  What were you trying to solve for with this new, with this new score?

• 48:10Speaker 02

  So trying to solve for the fact that as a nutrition scientist, I believe that the NOVA classification is not useful at an individual level, that it actually doesn't capture the health effects of a food, that it over-demonizes too many foods. So we needed something that actually really just captured food that's been processed in a way that does make it unhealthy, given that not all food processing is bad for us. Because that's something that for me, as a nutrition scientist, really worries me, that there's a scaremongering about anything that's packaged or processed is going to be bad. That's not the case. So we wanted to develop a score that could really target the worst of the processed foods. And I think that's really important, given that so many of our calories come from processed foods.

• 48:51Speaker 02

  We can't just tell everyone, hey, cut out all your calories, given the price difference, given also the enormous challenges there is to change the types of food you're eating. So we wanted to provide a score that really targeted the worst ones as a starting point.

• 49:06Speaker 00

  So after all of this work, and I know you've dug through this massive dataset that, you know, we've been collecting with all the amazing participants who are listening to this, this podcast, right? One, three hundred thousand people and all this other data. You've said you've sort of managed to get this to work. What have you come up with? And then I'd love to dig in a little bit into like, what are those components? That help us to understand actually what's causing the harms that are coming from ultra-processed food?

• 49:32Speaker 02

  So we've come up with a Zoe Processed Food Risk Score. It classifies food according to four levels. So the no risk, the low risk, the moderate risk and the high risk. And we have fed different features into this score that we know, based on the latest science, are relevant to how processing impacts our health. So this includes the number and the potential health risk from additives. So not just the number, but also how risky they might be. It includes energy intake rate. So basically how fast you're eating the food that also acts as a kind of surrogate for that texture of the food and the structure of the food. And then the third component is the hyperpalatability index as well.

• 50:17Speaker 00

  That was the bliss point that Tim was talking about earlier.

• 50:20Speaker 02

  So those three features feed into this score. And each food is graded based on the number of additives it has, but also the potential risk of each additive. Whether it's energy intake rate is above a specific threshold, which is seventy two calories per minute. I E. Do you consume more than seventy two calories per minute when you eat that food? And then whether it reaches those thresholds for hyperpalatability. So those mixtures of the fat, the salt, the car and the sugar.

• 50:49Speaker 01

  And eating rate was a bit of a combination of two things, wasn't it? It was like the density of the food and the speed at which you can consume it.

• 50:57Speaker 02

  So it ultimately tells you how many calories you're consuming per minute, not just how many grams of food you're consuming per minute. So these three features go into the model. There's like this little black box that works out, you know, where in the tree things go. And then you come up with each food where it sits within those processing food classes.

• 51:19Speaker 00

  That all sounds very complicated. So does that mean if you want to do this, you sort of need to do a lot of maths as you walk around the supermarket?

• 51:28Speaker 02

  It is really complicated. Yes, you would need to do a lot of maths because you'd need to work out the energy intake rate. You'd need to go and look at the scientific literature. You'd need to work out those ratios of those nutrients. But more importantly, you'd need to know, is there any risk from this additive? A lot of additives are labelled with E numbers in the UK. In the US, they typically have their full name. So soy lecithin, for example, which is an emulsifier that's used in the UK, also has an E number in the UK. Many people might be scared because they say it's an E number, it's bad. In the US, it might be something that they perceive as bad as well because they don't recognise the name and it sounds a bit chemically. But we've graded that and we've graded soy lecithin to actually be very low risk. But then we have other additives.

• 52:13Speaker 02

  So for example, ACEK, which is a common sweetener, we've graded to be a higher risk. And then we have ones that sit in the middle that we say are moderate risks. So mono and diglycerides, for example, are also used as emulsifiers. So it would be very difficult even for me to remember where all of these different additives fit. And that's because as part of this work, we went back and did a really thorough review of all of the latest evidence. So much of the safety guidance that's out there, that the government used to say whether an additive is safe to be put in our food is from this toxicology style of studies. So yes, it shows it's safe. But actually what we've done is gone that step further and looked at all the latest human studies to say, okay, it might be safe and not immediately causing us cancer.

• 52:58Speaker 02

  But is there now some suggestion that it might increase our risk of metabolic ill health? Or impact our microbiome negatively?

• 53:07Speaker 01

  What I think was really fascinating from the research that we ended up doing was seeing this top high risk group, which I think was about twenty five percent of the foods that had all these ingredients, you know, the manufacturers had thrown everything at it, all the things that make us overeat and buy more of their product. And they were the ones that seemed to have all the harmful effects clustered into them. So that they're the ones we should be focusing on. So rather than trying to cut out sixty percent of our food, you know, if we focused on that twenty five percent, get rid of them out of schools, got rid of them out of hospitals, you know,

• 53:48Speaker 01

  put warning labels on them, we'd be so much better off than trying to sort of muddy the water and think about everything. And what I also liked was we did some microbiome analysis, didn't we? That's just come through recently and showed that the big microbe effects are again in that top group, not in the lower risk ones. I've actually changed my practice a lot, my eating habits, what I choose in a supermarket. And, you know, I don't mean this to sound like an advert, Jonathan, but, you know, I do use my Zoe app when I'm going there, looking at some items in the supermarket that I haven't seen before. Say it's, so, you know, what's the best cheese biscuit to pick, for example?

• 54:32Speaker 01

  The only way to really do this accurately now is to identify those high risk groups with an app. The science is so complex, you really just can't do it even, you know, if you had a brilliant memory. It's very hard to do that for anything novel. So it's become part of my practice and I think this is one of the great advantages of AI and some of the latest science that we're getting.

• 54:55Speaker 00

  And let's say somebody's listening to this and they're in a country where the app isn't yet available or, you know, they just absolutely can't afford to use it. Because I think you're saying, both of you, this is really complex. And that's one of the reasons that you developed this science and it's sort of why you use the tool yourself. Are there any rough and ready rules they can use? And how much should they be worrying about? Like the bread that has like one preservative in versus those things that you're describing at the sort of high risk?

• 55:29Speaker 02

  I think my top tip that I always give to people is, does it look like the original food that it came from? Has the texture been changed so that it's very soft, almost predigested? I would caution against just focusing on the number of additives and emulsifiers because you could have a food that has one additive that we know isn't particularly good for you versus a food that might have three or four that we know are actually inert and harmless. So that's why it is so complex.

• 55:58Speaker 01

  Yeah, it is complicated. And this is why, you know, we need actually legislation. That's why our government shouldn't be just doing whatever the food industry tells them to do. They should be changing the labels and stopping them, putting, you know, low calorie, low fat, therefore it's healthy and disregarding everything else that they've put into it and changing the composition and made it baby food. So we need help, but until then, we need tools to do it. So I would say if you haven't got an app, look at the front of the pack. And if it says low cal, low fat, you know, no added sugar, that should probably tell you they've been fiddling a lot with your food. We're looking at rough guides. It doesn't mean there aren't exceptions and there are always exceptions in this.

• 56:42Speaker 01

  But if you're going in there, just be suspicious of anything that says that.

• 56:46Speaker 02

  And there's lots more to think about as well as a processing score. We still know that actually nutrients do matter. So for example, if you were to take lard or beef tallow, we know it's packed with saturated fat. And although it wouldn't be classed as an ultra-processed food, it's still bad for us. And so I really want to highlight that if people are using our app, that it does also as well as include the Processing Food Risk Score, all these other features of a food, such as the amount of polyphenols, the fibre in the food, the other nutrients and so forth. What we've done is actually validated in our own research from our own Zoe Predict studies,

• 57:26Speaker 02

  whether those foods that are in this higher risk category are actually associated with unfavorable health effects. And we've looked at this in thousands of people. And what we found is people who are consuming more of this high risk processed food according to our classification system tend to have a higher BMI. They tend to have a higher weight. They tend to have higher levels of inflammation, which I think is really interesting. And they also have a more unfavorable gut microbiome composition.

• 57:57Speaker 02

  And then when we find people who are consuming more of the processed food that fits into our low risk or no risk, we see the converse. They have lower weight, lower waist circumference, lower levels of inflammation, and they have a more favourable microbiome composition, even though that food has been processed.

• 58:17Speaker 00

  You said at the beginning that the first people to try and come up with a way to classify something as ultra-processed food, created this thing called NOVA, and that about sixty percent of the food that we're eating in the US or the UK is ultra-processed under that classification. But under the classification that you two have both been developing with all the latest data, actually, like the real ultra-processed food, this sort of high-risk ultra-processed food, there's still a lot of it, but actually it's about twenty-five percent of the food that has been eaten in the US and the UK.

• 58:50Speaker 02

  What we've seen in our dataset in the UK and the US, that only about twenty-five percent of our calories have been processed in such a way that we would say it's a higher-risk food. But I think what's also interesting is when we look at that sixty percent of calories that are coming from this other, the NOVA traditional classification, we would actually classify about thirty percent of those as being pretty harmless for us.

• 59:14Speaker 00

  So could you give me a few examples, maybe, of food that we've maybe been worrying is ultra-processed and sort of avoiding, and then actually you're now saying this is low risk?

• 59:25Speaker 02

  So in the UK and the US, lots of chocolate, even if it's dark chocolate, would be considered ultra-processed according to the NOVA classification. A lot of breakfast cereals would also be considered ultra-processed according to the NOVA classification. When we put that through our system, we find that some, not all, dark chocolate can come out as quite low risk. We also find a few, not all, nutty granolas, depends on the brand, some whole-grain cereals, again, very dependent on the brand, actually would come out as very low risk, yet they would have been, according to the old classification, classed as an ultra-processed food.

• 1:00:05Speaker 01

  Yeah, they're all lumped together and there's very different risks.

• 1:00:08Speaker 02

  Breads is another great example because it's such a broad food group. And according to the NOVA classification, any bread that's sold, made, purchased in a supermarket, packaged in a supermarket, would be classed as ultra-processed. But we know that actually it falls across a whole range of risks. Yes, there are some breads that have a lot of additives, emulsifiers, et cetera, that we would class as high risk, but there's also supermarket breads that we would say are no or low risk as well.

• 1:00:36Speaker 00

  I would love to wrap up with a question for, you know, for people who can't access the app and aren't able just to barcode scan, or even for people who do have the app but like don't want to scan everything as they're going through. Which are the three or four, like, food groups that are the worst offenders for where you would think that this food is going to be safe and healthy, and actually it turns out that there's all of this high-risk UPF that's hiding underneath it? And I ask because I've been shocked by this, and I would love for you to share this with all our listeners. I'll never forget the moment that everything shifted for me. I was at a public talk on nutrition,

• 1:01:18Speaker 00

  listening to a speaker explain that my gut had trillions of microbes in it, and that these bugs shaped every aspect of my health. That speaker was Professor Tim Spector, one of the world's top one hundred scientists, who became my co-founder here at Zoe. Nine years later, Zoe runs the world's largest gut health research study, and the conclusion is simple: gut health is health. How you feel, your long-term health and your digestion are all shaped by the state of your gut. As a listener to this show, you know how important it is to feed your good gut bugs. But I suspect that like me, you have a busy schedule, and often you feel you haven't given them all the different plants they crave. And that's exactly why we created Daily Thirty. It's a gut health supplement packed with over thirty plants that you sprinkle onto any meal.

• 1:02:03Speaker 00

  It tastes great, adds a satisfying crunch, and gives your gut the diversity it craves. Finally, a healthy, happy, that's easy to stick to. I should note, I take it every day. And because we're Zoe, we don't just guess, we test. We put our original Daily Thirty formula through a randomised controlled trial, the gold standard of testing. The results blew us away and proved it supports your digestion, energy and gut health. That trial helped us develop the formula we have today. Today, Daily Thirty is a non-negotiable daily habit for me. So don't put your health off for the future. Go to Zoe.com/daily30 and try it today.

• 1:02:42Speaker 02

  So I would say my top two contenders for this would be yogurts, because you can have your very natural Greek full-fat yoghurt, that I consider a very healthy food, and then you can have these artificially sweetened, full of all sorts of chemicals, low-fat, high-sugar fruit yogurts, but that look like they're healthy, the kind of yogurts that I might have fed my children ten years ago, despite all of my knowledge thinking that they were healthy. And then I would say another food group to be cautious of is cereals, breakfast cereals. So you can have some breakfast cereals that are actually quite healthy for you. So for example, Kellogg's All Brand Cereal,

• 1:03:25Speaker 02

  despite being a packaged cereal, actually would be no risk or low risk according to our classification. But then you can have many of these other breakfast cereals that have these claims that they're high in fibre, good for energy because they have a certain amount of zinc or whatever, but often actually very high in sugar and might have lots of other additives that I would not want to be feeding my children.

• 1:03:47Speaker 01

  Yeah, I think people increasingly are buying ready meals, and if you just look at the ingredients of those sauces, you're seeing this mixture of sugars, sweeteners, salts, unhealthy fats, and other children's products, really. Virtually everything for children specifically is designed to make them overeat and contains either sugars or sweeteners. Things like these fruit pouches that a lot of parents are giving toddlers have all sorts of things in you would

• 1:04:26Speaker 01

  want, they're high risk. So again, they might have a few camouflage with vitamins, et cetera.

• 1:04:33Speaker 00

  Are the manufacturers allowed to put sort of sweeteners into these products that you give to your kids?

• 1:04:40Speaker 01

  At the moment, manufacturers are nearly encouraged to add sweeteners to these products because they can then say they've reduced the sugar content. And parents are generally looking for something that's lower in sugar for their kids. So you're seeing all these complex artificial sweeteners and chemicals being ramped up to compensate. So more and more our kids are being subjected very early on, from birth onwards, to having these incredible chemical sweetening effects.

• 1:05:12Speaker 02

  I think it's really challenging because the government introduced a sugar tax a number of years ago in order to reduce the intake of added sugars in our diet, which we knew was becoming an increasing problem, particularly in children. The tax is at the level of the manufacturer rather than us as consumer. And so what many manufacturers have done is reduce the sugar in the food, so it falls below the taxation level, but they still need to keep that food sweet. So that's why we are seeing more and more sweeteners added to food to enable them not to take on that charge.

• 1:05:44Speaker 01

  The sugar tax hasn't hit dairy products yet. They're avoiding it. So it's actually the manufacturers doing it because they realise they can sell more.

• 1:05:52Speaker 00

  It is amazing how much this changes as you go from country to country. In the States, it's the worst. It's almost impossible, I find, when I'm going through, you know, the yoghurt aisle to find anything that doesn't have, you know, high-risk additives to it, even when you're trying to find, you know, the Greek yoghurt. It's amazing. Whereas, you know, I find that when I'm in, you know, more Mediterranean countries, there's a lot more food that doesn't have as much added in. And I think that's also related, I think, to how much we all eat ready meals, right? In the UK and the US and places like this, and countries where they're still cooking more from scratch. And so the other thing I'm shocked by is sauces. Again, that's a way to make life

• 1:06:34Speaker 00

  easier that I would historically have done a lot of, which is, you know, you cook some pasta and you throw like the pesto sauce on top. And I've realised that there's sauces I've happily used for decades, and I've been really shocked that they have sweeteners in them and all these sorts of things. And then you realise there is another sauce that's been sold next to it. I couldn't have told the difference, right? They all say pesto, made in Italy, looks the same. And I've now realised, like, one of them is stuffed full of things I never realised, and the other one is saying there's no risk and it's just got all of these natural ingredients. And that makes me quite angry that I'm supposed to play food detective rather than the supermarket

• 1:07:16Speaker 00

  just saying clearly, like, this thing is like the sort of food that my grandparents would have eaten, and this is full of all of these things that could only be made in a lab, and, you know, I can't find them. So it just feels as though, like, the experience I have outside of this podcast studio is so different from what I hear from you and all the other scientists about what we know is healthy. So I'm really excited by the score. And you may just, just to finish off, where is this in terms of sort of publishing results and peer review process and things like that?

• 1:07:51Speaker 02

  So our fabulous science team at Zoe have just finished validating the score, so looking at how our score is associated with various health outcomes. We've just finished that manuscript. We're about to submit it to a peer-reviewed journal, so it will be out soon. It's also really important to mention, Jonathan, that we're going to continue to evolve the score. So as we understand more from more research coming out about additives and emulsifiers, we'll continue to update it. And that's really, really important because you get so many diet and food scores out there that are fixed, but ours will update with every new study that comes out.

• 1:08:27Speaker 00

  Amazing. Let me try and do a summary. I think the first really big thing is there has been this real, like, earthquake in nutritional science, saying that actually this idea of ultra-processed food is real. And that's because of a number of big papers that have done this, like, direct comparison between two meals that have exactly the same amount of protein in carbs and fat, and yet you have this radical difference in terms of How much people eat and then actually real impact on their weight and their risks of diabetes. And I think that is extraordinary and is very cool that the science is continuing

• 1:09:07Speaker 00

  to get better. You talked about four papers. The one that is really sticking in my mind is this first one, this Kevin Hall paper, where you're saying that you had these people, you know, for two weeks, one UPF meal for two weeks, normal, they looked exactly the same, they had exactly the same of these macronutrients. But in the two weeks when you were eating the UPF, you ate 500 more calories each day and you ended up putting on like two pounds a kilogram in two weeks. But then if you went on to the normal one, you actually lost a kilogram. So it's like a two kilogram difference. And I'm like, well, you can pretty much understand the obesity epidemic, like just from this study, it's remarkable. Then you talked about this L N A study and the big takeaway for me is

• 1:09:52Speaker 00

  sweeteners aren't just this inert thing that does nothing, you know, which is the way I brought it up. It's changing your microbiome, it can increase your risk of diabetes. And then Sarah, you explain more broadly, it's not just sweeteners, there's emulsifiers and colorants and preservatives. And although we shouldn't worry that like one of those is going to give us cancer, actually, some of them are high risk if you're eating them over and over again. And as you're starting to add more and more of these together, you start to move to something that's really high risk. Then you talked about this brand new study, the restructure study that I'd never heard of before. And there you said you had these two meals, both of which actually were ultra processed food, but that allowed

• 1:10:33Speaker 00

  them to reformulate it so that one of them was very soft, you ate really fast, one of them was really chewy. And the one that was really soft, you ate an additional 369 calories a day. Whereas the other one, which is obviously more like real food, you start to feel full. And then finally, we talked about a final paper, the Fazino paper, we talked about this bliss point and said, you know what, potatoes on their own, who wants to eat that much of those, like oil on its own. No one sits and eats salt all on its own, right? But magically, you put them together in just the right combination. And I've eaten three bags and they worked on tobacco and now they're working on me. This is all complex. You spent the last two years building this new Zoe UPF score to identify what's high

• 1:11:18Speaker 00

  risk. And the good news is it's not 60% of all the food we eat. But the bad news is it's still 25% and it's hidden in a lot of foods. You can use the app to figure this out. And Tim, you were saying you do this because it is hard. But if you're listening to this and you you don't have access to the app, then there are particular products to watch out for. And the particular ones are not the ones that you know about for you. It's yogurts, it's cereals, it's ready meals. And I think the thing that is most shocking is it's children's products, like these are the areas you have to be most concerned. So it is a slightly concerning message. To finish on a, on, I think, on a positive note, you're not saying that if you eat an occasional thing with UPF, that this is going to

• 1:12:03Speaker 01

  No, it's as a treat, you know, we all shouldn't be too obsessed about just having the occasional ultra processed drink or a snack or a biscuit or a cookie, whatever it is. Every now and again, I don't think there's any evidence that's bad for you. But it's that continuous use, particularly from children onwards, you know, for decades, that's really what we're talking about. It's about changing these habits lifelong.

• 1:12:29Speaker 02

  And Jonathan, I'd love to add three points to your recap. One is that I think it's really important that we should not fear food that's been processed. Just because it's been processed does not mean it's bad for us. And I think it's also important to reiterate as well, that heavily processed food does tend to be cheaper. And this is a big problem that we have to solve for. We at Zoe can't solve for this, but it's a problem that has to be solved for in many countries. And then the the last thing I want to mention is yes, we should all be cooking from scratch. We should all be making our tomato pasta sauce at home. But it's challenging with the way that we live our lives. So I think there's lots of things conspiring against us, but ultimately do not be scared of all processed food.

• 1:13:33Speaker 00

  When you think of a gut supplement, what comes to mind? Something you swallow and grimace at. I think the aftertaste is so horrible, it must be good for me. Or something you sprinkle crunch and actually enjoy. Daily 30 is Zoe's gut supplement. Years of scientific research have gone into creating the crunchy and delicious blend that we sell today. Developed by Zoe's gut health scientists, Daily 30 is a gut supplement that's rewriting the rules on supplements by rejecting synthetic chemicals. It's packed with over 30 carefully selected plants and features ingredients that support gut health, digestion and energy. And because we're Zoe, we lead with the evidence. When we first developed Daily

• 1:14:16Speaker 00

  30, we ran our own randomized controlled trial to check if it worked. The results blew us away and helped us create the formulation that we sell today. By the way, whenever we talk about Daily 30 is a good source of fibre, we're required to say that it contains four grams of total fat per serving. Obviously, that's all amazing healthy fats from plants. To get your pouch of Zoe's delicious gut supplement, visit zoe.com/daily30. Thanks for listening and see you next time.