Here is the full transcript of medical doctor Chris Van Tulleken’s talk titled “The Harsh Reality of Ultra Processed Food” at Ri conference on 19 September 2023.
Listen to the audio version here:
TRANSCRIPT:
Well, thank you all very much for coming. I’m impossibly honoured to be here at the Ri, I’ve attended many wonderful lectures here. I want to talk about food and about stuff that isn’t food. But before we do that I want to discuss a little bit about the language we use for this discussion, because I’m going to talk about the wide effects of this category of ultra-processed food on human health and on planetary health, but the thing that a lot of people want to understand and the thing that a lot of the research is focused on is weight and obesity.
We don’t really have the language to talk about this in a sensitive way, the language is still evolving and if we’re not really, really careful, a war on obesity very quickly becomes a war on people, because more than anything else we use the word obesity in its adjectival form. People are obese, so obesity and identity are conflated.
And so when we tackle obesity, if we say that food is the problem, the people who eat it can quickly become the problem as we see in this headline from the Daily Express. So what I want to do is use the framing of this, that people can live with obesity, we all live, many of us live with lots of problems and obesity needn’t be an identity, it’s an identity that people can put up and they can pick it up and they can put it down in different contexts.
It’s the leading cause of early death for of course the animals we eat, it’s also the leading cause of early death for all the animals that we don’t eat, because ultra processed food and the food system that supplies it is the leading cause of loss of biodiversity. So this is a really, really important discussion to have and while the solutions to this problem are going to be really complicated and I’m going to explain why they’re so complicated, they’re going to need to be local and nuanced and driven by grassroots activism. And they’re going to need to deeply understand all of us and what we want and what we need and they’re going to involve politics and economics and culture. The cause of this pandemic of diet related disease is pretty simple.
The Rise of Ultra-Processed Foods
I want to make the case to all of you today and to anyone watching that the primary cause of pandemic diet related disease, including obesity and malnutrition, the primary cause is the rise of a diet of industrially produced edible substances known formally as ultra processed foods. I want to make the case that obesity and diet related disease is therefore commerciogenic, it’s driven by profit incentives and more and more my research focuses on working with economists and with agriculturalists to understand how financial incentives drive this pandemic.
But unless we frame the problem as commercial in origin, we will never solve it. And so I draw the parallel with tobacco because I think we have to start thinking about treating the companies that make our food a little bit in the way that we treat other companies that interact with our health, the oil industry and particularly the tobacco industry.
You are all part of an experiment that you didn’t volunteer for, we’re all being trialed constantly using brand new molecules which have never been in our diet before and new formulations of ancient molecules that have never been tried in a formulation. You have an internal evolved system to deal with food that isn’t very good at dealing with these foods.
“The Easy Way to Quit Smoking”
In my book, I explicitly link, I try and write it using the techniques that developed in this best-selling book called “The Easy Way to Quit Smoking.” Has anyone here ever read this book or used it to quit smoking? Yeah, it’s very popular and it’s unique in the self-help genre because it’s the only book recommended by the World Health Organization as a well-evidenced way of quitting smoking.
I put up a few research studies there, this book actually seems to be in some studies as effective as nicotine patches or therapy or lots of the other methods we use. Part of the trick in this book is that you’re advised to keep smoking while you read the book. At the heart of my book is an invitation to participate in the experiment, you’re already doing it, ultra-processed foods make up a huge proportion of what we eat, but to do it for yourself, so keep eating while you read.
If you don’t want to buy the book, lots of people can’t afford my book, there are some amazing resources online. There’s B. Wilson’s resource in The Guardian, the long read on ultra-processed food, which had huge influence on me. So you can read about ultra-processed food and I would encourage you to engage with it because that was the experiment that I did when I was writing the book, is I went on a month-long diet of ultra-processed food.
And I didn’t do that casually, I didn’t do it as a stunt for a teleprogram, I did it to gather pilot data for a much bigger study that we’re now running at UCL. So I did it with the help of very expert colleagues, and I’ll talk a little bit about what happened to me in that diet. So I’ve written the book with that in mind, we’re part of this experiment.
Processed vs. Ultra-Processed Food
A thing that’s really important to understand early on is that processed food is not the same as ultra-processed food. Processing is ancient, humans are the only obligate processivals, we must process our food. So we have out there some guts of different animals of comparative size, some of them.
Humans compared to other animals of similar size and weight, we have tiny jaws, minuscule teeth and very short digestive tracts. We have extended our gastrointestinal system, our digestive system, out into our kitchens. We use grinders and knives to chop and cut our food instead of our teeth and our jaws. We use cooking and processing and mashing and extracting to make our food much more easy to digest.
And so modern food was invented primarily by female scientists over hundreds of millennia, and they worked in caves and leaf shelters and huts and then modern kitchens to invent the modern diet. And it involves a huge amount of processing. For over a million years we’ve been cooking food, and for hundreds of thousands of years we’ve been grinding it and mashing it and extracting it and salting it and curing it and fermenting it and smoking it and doing all of these wonderful things that make diets edible and delicious.
And we’re very sure that every traditional diet that we’ve ever studied is associated with really good health. You can go to East Asia and look at pescatarian diets or South Asia and look at vegan diets. You can go to the high Arctic and look at diets that comprise mainly fats from sea mammals and are primarily carnivorous diets. All of them seem to be associated with good health. Of course, there’s the Mediterranean diet as well.
What we’ve never been able to do is to extract any molecule from any of those diets and show that it has any benefit in healthy people, and that’s really, really important. So when we talk about food, I’m much less interested in individual products or individual components of food than I am in a dietary pattern. The food we eat is, we never eat individual food.
So whenever we’re talking about food, people always want to know, is broccoli healthier than burgers? Well, if you’re on a desert island, you’d be much, much better off eating burgers. You could live your entire life on burgers. If the meat was rare, it would have vitamin C in it. They’re a good source of all kinds of things. They’ve got loads of calories. You wouldn’t live long on broccoli. Broccoli is deficient in all kinds of essential fats. It’s very low in protein.
And yet broccoli forms a key part of a really healthy, balanced diet in a way that’s an ultra-processed burger wouldn’t. Processing is ancient, therefore, and has shaped our genes, our physiology. But ultra-processing is very different.
The Third Age of Eating
So we have now entered what in my book I describe as the third age of eating. In the first age of eating, creatures, microorganisms ate stuff that had never been alive. Bugs ate rocks. In the second age of eating, people eat food. So organisms created a shortcut where we eat things that have been alive. And the second age of eating continues today. You can go into any big supermarket and you can buy things that used to be alive and you can assemble them at home into a diet.
Ultra-processed food is where we eat things that have never been in our diet before. And I’m going to explain what they are. Using photos in these talks, especially about weight and diet, can be really stigmatizing. The only people I’m going to stigmatize are my own two kids. That’s Sasha. She’s now three. And she is very much a child of the ultra-processed food age. She’s grown up eating lots of it.
Ultra-Processed Pet Food
There she’s eating ultra-processed food. It’s ultra-processed cat food. So this is now… She’s a huge fan of it. And I have friends who work, I have lots of friends in the food industry, I have friends who have worked in the pet food divisions and moved over to the human food divisions. And we use the same flavoring technologies in both. So ways of getting pets to like food, great ways of getting kids to like food.
And Sasha was a huge fan of this particular… It was a kibble for cats with poor dentition. Anyway, so there she is. And you may find I’ve got a lot of messages from people who, having engaged with the book, have switched their perpetually hungry domestic pets to whole food. And it’s very expensive to do it. There are environmental concerns about doing it. But they found a lot of their pets become much more satisfied eating real food. That’s an anecdote.
Defining Ultra-Processed Food
So what is ultra-processed food? I’m happy to talk more about the controversy about the definition. In fact, the definition in terms of independent scientists is extremely widely agreed on.
UNICEF, who I work with, the World Health Organization, who I’m on an expert advisory panel for, research groups at Harvard, Oxford, my group at University College in London, Cambridge, all over the world have agreed that this is a great and useful way of defining a category of food. It came out of work in Brazil. Don’t worry about trying to read this, by the way. I’m putting it up there to make it clear that the definition is extremely long.
If it’s too long to read, here’s a really good working definition that some of you will know, of course. Wrapped in plastic with at least one ingredient you wouldn’t normally find in a standard home kitchen. It’s almost certainly ultra-processed.
The Impact of Ultra-Processed Foods
The definition came out of a research group in Brazil led by someone called Carlos Montero. And a lot of the best work on UPF has been done by research groups in South and Central America. Because in lots of countries, Mexico, Brazil, Colombia, Chile, they found that in a very short space of time, obesity and metabolic disease like type 2 diabetes went from being essentially unheard of, they just didn’t really exist, to in the space of around a decade being the dominant public health problem.
And the only thing that had happened was the incursion of a Western American industrialized diet where most of the calories were coming from ultra-processed food. So it was a really, really powerful natural experiment. Carlos Montero was a very senior nutritional professor in Brazil, he’s a medical doctor as well. And he collected the data and derived this definition from the data that he was seeing in the public health research that he was doing.
So the definition’s very long. There was a bit of social theory baked into this. I’ll expand the definition a bit. But in paragraph 9, it makes it clear that the purpose, part of the purpose of the food is profit. That we make this food so it is easily marketed and easy to sell. So this was a huge paradigm shift in nutrition.
Because everyone here in this room, I would bet, has thought for most of your life about nutrition in terms of about four things. Salt, sugar and carbs, fat, protein and fiber. Those are the things that our food is made up of, and that’s the way our food is labeled.
A Paradigm Shift in Nutrition
And that’s what nutrition is, it’s about the nutritional components. Carlos Montero was proposing that food is more than the sum of its component parts. That what we do to the food actually matters. And this was revolutionary, and we’re going to see why. So we’re having a conversation where we need sensitivity, kindness, nuance, scientific sophistication and to use lots of different siloed knowledge. So I thought who better to turn to for this kind of thought than the words of former and perhaps future president Donald Trump.
Donald Trump was one of the early adopters of the idea that ultra-processing had a significant effect on human health. So in 2012, he sent out a series of tweets. I won’t do an impression. No, I really want to. I’ve never seen a thin person drinking Diet Coke. The next day, he sent out another one.
Donald Trump’s Tweets on Diet Coke
The more Diet Coke, Diet Pepsi, etc. that you drink, the more weight you gain. The next day, another one. That Diet Coke tweet had a monster response. Damn it, I wish the stuff worked. The next day, the Coca-Cola company is not happy with me. That’s okay. I’ll keep drinking that garbage.
Then he let it rest for a few days and came back with, I think, a tweet that in just 140 characters, less than 140 characters, sums up more than a decade later the state of the art, the state of the science that we now have about non-nutritive sweetness. People are going crazy with my comments on Diet Coke, soda. Let’s face it, this stuff just doesn’t work. It makes you hungry. Now, that was the face he pulled as he sent the tweet.
Understanding Diet Coke and Ultra-Processed Food
So my proposition to you is if you can understand Diet Coke and how it interacts with your body, then you’re a long way into understanding what ultra-precious food is. This is Diet Coke labeling from the United Kingdom, but this is more or less how it’s marketed around the world. This gets four green traffic lights on the bottle.
So this isn’t just a health food. This is the healthiest product you can possibly buy. Very few foods get four green traffic lights. It’s a sparkling, low-calorie soft drink with vegetable extracts with sweetness. Let’s read the ingredients. Carbonated water. Fine. Now, caramel E150D might make you think of creme brulee, of traditional treats, of 19th century French cooking. In fact, it has nothing to do with caramel. It’s carbohydrate being put through a set of industrial processes using chemical modifications with acids, alkalis, and heat. It contains ammonia. It contains sulfites.
And you can read more about it on the WHO Committee on Food Additives website. There are sweeteners, aspartame and acesulfame K. Now, aspartame hit the headlines recently because of concerns that it seems to be carcinogenic. There’s some nuance about that. I’m not very concerned about its carcinogenic properties. Much more important was a very significant paper published in one of the world’s leading scientific journals this summer, Cell.
The Effects of Non-Nutritive Sweeteners
And it was an analysis of what the non-nutritive, or we call them artificial, but the natural ones do the same thing, is what non-nutritive sweeteners do to our health. So we now think, if you look at the independent studies, the non-industry funded ones, there is something that seems to be really tricky for the body. When you put sweet taste on the tongue, which you haven’t just evolved for fun, right? We’ve really evolved a sophisticated internal system for detecting what food does.
So when you taste sweetness on your tongue, it prepares your body to receive sugar, to receive refined carbohydrates. And humans have been eating significant quantities of refined carbohydrates for many, many millennia. When that sugar doesn’t arrive, it seems to cause problems. So people used to think that the problem was that you released insulin, and that dropped your blood glucose, because insulin lowers blood glucose, and that made you hungry, and you then went and ate more carbohydrates, and that might be why they don’t seem to promote weight loss.
It seems now, from the research this summer, that a lot of them actually increase your blood glucose. And we’re not really sure why that is. It may be part of a stress response. The brain is a prediction engine, it’s constantly making predictions about the world. When you get a mismatch between a prediction, like sugar is on its way, and the sugar doesn’t arrive, there may be a stress response.
The Unhealthy Ingredients in Diet Coke
No one really knows. But the artificial sweeteners, according to the World Health Organization, and I think the best evidence, don’t seem to be metabolically superior to sugar, and they don’t seem to be linked to significant weight loss, and that is a huge problem. There are natural flavorings, including caffeine. I mean, I would claim caffeine is an addictive stimulant, but, you know, whatever you like.
There’s phosphoric acid. Now, it’s particularly significant for the people born women in the audience. Phosphoric acid doesn’t just dissolve your teeth. It can also leach minerals out of your bones, and reduce bone density, and citric acid will also dissolve your teeth. This is not a healthy product. It will not help anyone lose weight. It is a way of commodifying ill health, I would frame it as. So let’s look at the logic of UPF.
Reading Ingredient Labels
This is what I want you all to start doing. In fact, what I’m sure you will all start doing, is you’re going to go out of here, and you’re going to start reading ingredients packets. Some of you may already be obsessively doing this, because there’s been a lot of coverage about UPF in the last six months.
You will notice that themes, tropes, emerge as you read these ingredients lists. They all start with commodity crops. We only eat a tiny number of plants. Our carbs come from four plants, rice, corn, soy, and wheat. They might be mixed with some commodity oils. There’s a short list of them, there’s palm, sunflower, some mixed vegetable oils.
The Process of Making Ultra-Processed Foods
You take those crops, and you, this is the Mato Grosso in Brazil, by the way. So this is, that’s primary forest on the right of the picture, and then on the left is the soy plantations. So you grow these crops at scale. They’re often fed to animals. Corn, soy, they’re animal food. And you take leftovers, and to add value to them, you put them into the human food chain.
So you break your crop, whether it’s corn or soy, you break it down into powders of fats, proteins, and carbohydrates. Now to assemble, they have a nearly infinite shelf life, and they cost very, very little. You can ship them all over the world in enormous quantities. Now to make them edible again, you can mix them with a little bit of meat. If you want, we eat three animals mainly. You could mix them with some fish, but primarily we just eat beef, chicken, and pork.
The Use of Additives in Ultra-Processed Foods
But you then need the additives. In the UK and in Europe, we have around 2,500 additives that we use in food, and they’re somewhat regulated. In the United States, there are between 5,000 and 15,000 additives. No one has a list. The FDA, who regulate or are supposed to regulate additives, don’t have a list of all the additives that are added to food.
But the additives broadly, the ones you’ll notice, is they emulsify and they stabilize. They bind those basic ingredients together, and they create textures. And then you can press them, extrude them, fry them, bake them, and turn them into any shape you want. These ingredient lists will be the same from your breads, to your cakes, to your puddings, to your pizzas, to your ready meals. They will all have the same basic ingredients patterns. Cheap crop, additives to make it edible. So let’s look at some examples.
Examples of Ultra-Processed Foods
Now, some ultra-processed food is really kind of obvious. I’ve used the word junk there. It’s a bit pejorative about Miss Molly’s, but some of it we might casually refer to as junk food. And you’ll see there on that list of ingredients, we start with some dairy fat, and then there’s this reconstituted whey powder. Whey powder was a waste by-product of the dairy industry for a long time. Adding it used to be spread on fields or fed to animals.
Now, if you can add it to food, it has huge value. Glucose syrup, sugar, dextrose, so three different kinds of sugar. Palm steering, palm oil, palm kernel oil, different oils. Emulsified, stabilized, flavoured, and coloured. Palm oil, of course, is a traditional ingredient. Many of you may have eaten it. It’s used widely across Western Central Africa where I’ve eaten it. There’s a bottle of it there.
The palm oil, palm steering, or palm fat that you’ll see on your biscuits in almost everything you can read, is nothing to do with that spicy, red, traditional liquid that you see there on your left. It’s been through an edible oil refinery.
The Processing of Palm Oil
And there’s a picture there in the middle. They look like crude oil refineries. And it’s turned into, that’s palm steering on the left. So using processes of refining, bleaching, deodorizing, inter-esterifying, and hydrogenating, you can take any oil you want from any palm. You’ll see mango kernel oil on your biscuits. You’ll see shear oil.
You’ll see coconut fats. You’ll see palm fats. You put it through the RBD process, and you can create any melting point, any texture, anything you want, and it all tastes of nothing. So it becomes a way of adding fat to food that is extraordinarily cheap. But a lot of ultra-processed food is sold to us as being healthy. So I’ve used an Eat Natural bar, but almost all of these snack bars that are marketed to us are, in fact, ultra-processed.
Examples of Ultra-Processed Foods Marketed as Healthy
There’s a Nutri-Grain bar. Marketed as strawberry, there’s a picture of a strawberry there. It’s just 5% strawberry. And it’s that same list of cereal flours, vegetable oils, sugars, all stabilized and emulsified together. This might be my favorite example, because this was my favorite sandwich for a long time. And this is a brand that we associate with organic food, with good health.
And I’m constantly having a debate about what the riskiest kind of ultra-processed food is. Is it the stuff that we know is harmful for us? Or is it this stuff that we think is probably quite healthy, but which contains mono- and diacetyl tartaric acid esters, mono- and diglycerides of fatty acids? And that’s datum, that’s one of the most common emulsifiers that means that almost all the bread you buy in a supermarket will be ultra-processed food. In the UK, ultra-processed food is now most of what we eat. 60% of our calories come from ultra-processed food.
The Prevalence and Accessibility of Ultra-Processed Foods
80% is typical for teens. One in five people in this country get 80% of their calories from ultra-processed food. For many, many people, particularly those living in disadvantage, those with low incomes, this is the only food that is available, and it’s the only food that’s affordable. And we have libraries of data on that. And there’s often a politician who is happy to explain to us that lentils or porridge are very cheap to buy. You can make a meal out of pasta and some tomatoes.
And what’s never factored into that calculation is the fact that you need energy to cook that food, you need skills, you need a chopping board, you need a knife. You need to make it in quantity. No one makes a bowl of pasta. You need to make it in quantity. Put it in some Tupperware that you need to buy. Stick it in a chest freezer that you don’t have.
The Cost and Effort of Preparing Real Food
Real food is fantastically expensive. It spoils very quickly. And time is money. It takes a long time to prepare it. So never let anyone tell you that real food can be made cheaply. It is enormously expensive. So what are the effects on our health? The most important effect that most of us are concerned with is it seems to cause unhealthy weight gain. And this is a really important study. So lots of the evidence I’m gonna show you is epidemiological, it’s population studies.
The best evidence we have in science is when we do randomized controlled trials. And this was a really excellent randomized controlled trial undertaken by a guy called Kevin Hall who’s one of the world’s leading nutritional scientists. He’s an ex-physicist.
A Study on the Effects of Ultra-Processed Food on Weight Gain
He works in the States at the National Institutes of Health. And he did what’s called a crossover design. So it was as if we took this room, he’s fewer people, and we cut you in half and we said, you guys are all gonna eat an unprocessed diet for two weeks. And you’re gonna be locked in our lab and you’re gonna have an unprocessed diet and you’re gonna have access to 5,000 calories a day. And you guys are gonna eat an ultra processed diet for two weeks. And you’re also gonna have access to 5,000 calories a day.
So you all get far more food than you could possibly want. And the two diets are the same for fat, salt, sugar, and fiber. And the two diets are equally delicious. And you all agreed on this. You’ve all tried it and you all say the same thing. And after two weeks are up, you’re all gonna swap over and we’re gonna see what happens.
The Results of the Study
And these are pictures of the diet. And I know Kevin and I’ve said to Kevin, it looks almost like you tried to rig it because lots of people would much rather eat the food that’s on your right than on your left. And Kevin said, well, that actually isn’t the tool. We really studied hard and did lots of focus group testing to make sure that both plates were equally palatable. And this is what happened. This is just the weight graph.
You can see that just over two weeks, there was almost a kilogram weight change for the two groups in opposite directions over just two weeks. The group on the ultra-processed diet ate around 500 calories more per day, despite saying the food was equally delicious, despite the fact that both diets had the same amount of salt, fat, sugar, and fiber. So there is something beyond the salt, fat, sugar, and fiber, and something beyond the amount that people liked it, that was driving this excess consumption.
The Association Between Ultra-Processed Food and Various Diseases
But ultra-processed food doesn’t just cause obesity. Now I’m using the word cause here because I think the evidence we have has met the threshold for causality. And I’m happy to discuss, I think this is probably a pretty scientifically literate audience.
What we should probably say is that ultra-processed food is strongly associated with this very long list of different diseases, cardiovascular disease, cancers, all cancers, but particularly breast, prostate, and colon. Metabolic disease, like type 2 diabetes, obesity, high blood pressure, gestational diabetes, fatty liver disease, inflammatory bowel disease, anxiety, depression, frailty, irritable bowel syndrome, and lots of those other gastrointestinal complaints that we all just think are a part of growing old and being a normal 45-year-old. Dementia and an increased risk of early death.
This is a paper published by my PhD student, Sam Dicken. It’s a really important study. What Sam did is a formal review, and every single one of the studies that is used to generate that evidence controlled for fat, salt, sugar, fiber, and dietary pattern. They also control for educational standards and poverty and gender and age. So while those studies have flaws, no epidemiology is perfect. It’s really hard to correct for all those biases.
We have very, very good evidence that there is more than just fat, salt, sugar, and fiber that is mediating these harmful effects. Processing is important, and that this is a revolutionary way of thinking about food should, I think, surprise all of you. Perhaps the best example of why processing is important.
An Experiment on the Effects of Processing on Apples
It was an experiment done in the 70s by a group in Bristol. It was a very simple experiment. They got some apples, and they left them unprocessed, and they chopped them into chunks, and then they pureed them, and then they pureed them and squashed the fiber out. They looked at the effects of the nutrient, and they did it all immediately before participants drank or ate them.
And what we see is that when you eat a whole apple, you feel much fuller for much longer. Do get it if you need to, don’t worry about me. If you eat a whole apple, it leaves you feeling fuller for longer, it doesn’t spike your blood sugar, and you don’t get a sort of rebound hypoglycemia. If you drink the apple juice, you get a big spike of blood sugar, you don’t feel full at all.
Now, when you back out the fiber, so it’s whole pureed apple, you still get that sugar spike, you still don’t feel satisfied. So even when we have a pureed whole apple, it’s very, very different to eating the whole apple, to dismantling the apple with your teeth. Eating, the act of chewing, of manipulating food with your tongue causes all sorts of internal physiological changes that are really, really important. So we do need to process food with our mouths. Processing does affect nutrition.
Addressing Other Proposed Causes of Obesity
Now, before we go on, when we’re talking about obesity, we have to address some elephants, because there are some other proposed causes of pandemic obesity. So if I’m here saying the primary cause, perhaps not the entire cause, but the primary cause of the obesity change that we’ve seen since the 1970s, where childhood obesity was around 1% or 2%, the fact that obesity in childhood is now more than 20%, around a tenfold increase, that that tenfold increase is due to ultra-processed foods, I have to answer some questions. You should all have some questions.
Like, well, what about exercise? I mean, exercise is medicine. We’ve all become far less active. Our jobs have become automated. None of us work in heavy industry. Very few of us are out tilling fields. Even farmers get to sit in mechanized processes these days. So it seems very obvious that if we live more active lives, we must surely burn more calories. And that’s a picture of me filming a television series I did a very long time ago that some of you may have seen. They’re called Medicine Men Go Wild. And we went, my brother and I went and lived with remote indigenous peoples all around the world to learn about their food and their diet and their medicine. And we got far more out, we learned far more from these communities than we could possibly ever give them.
A Study on Calorie Expenditure in Hunter-Gatherers
So I went and lived as a hunter-gatherer in the rainforest at the borders between Brazzaville, Congo and Central African Republic for several months. And a scientist called Herman Pontzer did quite a similar thing. He went to live with Hadza hunter-gatherers in Tanzania. The question he wanted to answer was, how much more calories do they burn than we burn? It seems very obvious that hunter-gatherers would burn more.
And what he found was that for someone of the same sex, body composition and age, they don’t seem to burn any more calories when they’re running 14 kilometers a day, hunting antelope or digging tubers out of the ground. And he was so puzzled by this data, he went back and reanalyzed it all.
And then he reviewed the literature and we have studies going back to the 1990s. Some of them compare subsistence farmers to similar populations of, to match the populations in the States and find exactly the same thing. The subsistence farmers don’t burn many more calories. In fact, all the studies we’ve ever done using a technique called the double-labeled water technique have shown more or less the same thing, that over the long term, increases in activity that we do for a very long time don’t seem to substantially increase the number of calories we burn.
Now this would seem, especially in this setting, to violate the laws of physics. But Pontzer came up with a really, really good theoretical explanation of why this seems to be true.
The Benefits of Exercise Beyond Calorie Expenditure
Exercise is good for us, not because we burn more calories, but because we steal calories from other budgets. So I’m a 85 kilogram, 45 year old man. I burn around 3000 calories a day. And I do that whether I’m here or I’m in Tanzania. Now, if I were to move to Tanzania, I would spend many of those calories moving around, preparing food, hunting food, gathering food. In the UK, I still spend the calories, but I’m not moving.
So I seem to spend on inflammation and anxiety and on hormone levels that may be quite toxic. And there’s lots and lots of data coalescing around this. And Pontzer‘s theory makes sense in two ways. First of all, it explains evolutionary something really, really important.
The Evolutionary Explanation for Calorie Expenditure
That when food is scarce, you wouldn’t burn more calories to get it. So it would be really peculiar if we had evolved in times of scarcity to have to expend more energy gathering scarce food. Instead, we steal from reproductive budgets. We steal from immune budgets. So it’s coherent with evolution. It also explains why exercise is good for us and the benefit we all feel, which is that it damps down inflammation, pain, anxiety, and has all these other benefits.
It also explains all the data and the lived experience, I’m sure, of people here, that exercise isn’t a great way of losing weight. We’ve done lots of trials of this. You can show it’s quite a good way of helping to maintain weight loss, but it’s not a great way of promoting weight loss. And so he made a huge contribution to the literature. That was published in Science, and it’s really, really robust science. There’s some details that need tidying up, but it is very robust.
Exceptions to the Calorie Expenditure Theory
I should say some exceptions. I’ve also done arctic exploration, or if we look at elite athletes, they do burn more calories. You can increase your calorific expenditure briefly, you just can’t do it for very long. So exercise, if you do it intensively at a high level, you will burn more calories.
So where does this idea, because I was very surprised by this, where did my idea, as someone who spent six years at medical school, I spent five years doing a PhD, and I was sure this wasn’t the way I understood the body, and I think it’s probably not the way you will understand the body. What about the idea that exercise, you know, calories in, calories out, that the obesity pandemic is partly due to inactivity?
The Influence of Coca-Cola on Exercise Science
Well, the exercise is medicine phrase is actually trademarked. It’s trademarked by the Coca-Cola company. And it was a partnership with the American College of Sports Medicine and Coca-Cola. It was a huge public health program. And some colleagues of mine at the London School of Hygiene and Tropical Medicine, very senior group of scientists there, particularly Martin McKee, they did a network analysis to look at Coca-Cola’s scientific funding, because they noticed Coca-Cola was funding scientific conferences. They did some freedom of information requests.
There are hundreds of papers in the scientific literature, all of them promoting this idea of energy balance, that we can drink some fizzy, calorific liquid, and then we can run it off. And this is why Coke sponsors so many different sporting events. So the entire understanding of calories in, calories out, in part comes from this network of research funded by Coca-Cola. There’s very little other evidence to support it. And I would say that the best people in nutrition, when it comes to obesity, no one serious believes that inactivity is a significant contributor to pandemic obesity.
The Fallacy of Willpower in Obesity
What about willpower? We hear a lot about willpower. Now, what I want to do is equip you as a room to destroy people who bring up willpower, who say that, well, they often mix it in with calories in, calories out. It’s just all about effort. And people who don’t live with obesity have the daily experience that they use a bit of willpower to just decline the food. It’s entirely untrue.
That, by the way, is my daughter, Sasha. She is not blessed with any amount of willpower. What you’re looking at there is some US data. And you don’t have to look at the details of the graph, but it’s a graph of prevalence of obesity by date. And you’ll see there’s a sudden inflection point where all those lines on the graph go up in the mid-70s. That’s when weight gain took off.
Now, there are different lines on the graph because they’re men and women of different ages. Now, that’s a graph of the Caucasian part of the population, but the graphs for black groups and Hispanic groups look exactly the same. So at some point in the mid-1970s, something happened which made everyone across every age, in both genders, across all demographics, start to gain weight at the same time.
The Marshmallow Test and Poverty
Now, unless you propose that simultaneously there was some failure of moral responsibility in all those different communities, the willpower argument doesn’t stack up. It really doesn’t. We have a huge amount of data that willpower is usually a proxy for poverty, that people who live in poverty make very, very sensible decisions.
And particularly a lot of, many of you may have heard of this experiment, the marshmallow test, where you give a child a marshmallow and you say, if you don’t eat the marshmallow, I’m gonna leave the room. If you don’t eat the marshmallow, when I come back, you can have another marshmallow. And the children who are unable to resist the marshmallow, as they were followed over a very long time period, and this predicted an awful lot about their life courses, predicted their jobs, their incomes, and their weight.
And so this provided this evidence that people without willpower do seem to gain weight. In fact, there was a reanalysis of the data, and there’s a lot of nuance around this. So I say this with some caution. But when the data was reanalyzed, what they hadn’t controlled for was the educational level of the mothers. And essentially, if you are born into poverty, you make the sensible decision to take rewards when they are available. Because often, in contexts of poverty and deprivation, promises aren’t fulfilled.
And so you’re really smart to take that marshmallow. The kids were making smart choices. When you adjusted for that, the effect more or less went away. Willpower is something we have very few ways of measuring. It’s not an interesting part of this discussion. My patients who have lost weight have frequently lost their own body weight many times over. They exhibit far more willpower every day than I do. Personal responsibility, especially in terms of policy, has no place in this discussion.
Stress, Genes, and Ultra-Processed Food
What about stress and genes? This comes up a lot because I have, whether it’s patients or friends, a lot of people say to me, look, I know you think it’s UPF, but I eat for emotional reasons. I eat because I’m traumatized. I eat when I’m stressed. Ultraprocessed food is a little like tobacco in that sense. It’s one of the ways that the harms of poverty, of stress, of trauma, are made manifest.
So it’s always the ultraprocessed products that people eating for emotional reasons turn to. In the same way, tobacco products, or drugs of abuse, or alcohol, those are the substances that people turn to. And I’ll talk more about addiction.
So the deep cause of a huge amount of the pandemic of diet-related disease is poverty. But it is the marketing of ultraprocessed food, along with the marketing of gambling, tobacco, alcohol products, these other harmful substances that causes the proximate harm. But if we could fix poverty, we would deal with, the data shows, around about half of the problem. And poverty, I think, is a political choice that we can deal with.
So I hope I’ve persuaded you that UPF does harm us, that it is the primary driver, and that those other questions that swirl around the debate and confuse us, can actually, we can use evidence to get rid of them pretty effectively.
How Ultra-Processed Food Causes Harm
But how does ultraprocessed food cause its harms? Well, one of the effects is it’s very soft. It’s very soft, and it’s very energy-dense. And the way of testing this is to go and buy a loaf of this kind of bread, and I’ve put up hobbits, but you can, this is, because this is the bread that I always used to buy, and go and buy a loaf of sourdough, or rye bread, or any traditional real bread. What you’ll find is the emulsified supermarket bread takes about twice as long, or three times as long, sorry, it’s about three times quicker to eat. It’s very fast to eat.
Now, the softness has two effects. Partly, there’s a particle-size difference. We absorb ultraprocessed food very, very quickly because all the bits of real food have been fractionated down virtually into their molecular constituents. But it also means we eat it very, very fast. And we have very, very good data. Going back to the 1990s, that soft food that is quickly consumed is strongly linked with weight gain, especially when that food is energy-dense.
The Dryness and Energy Density of Ultra-Processed Food
And the other thing about ultraprocessed food, it is bone-dry. Real food is wet. Almost all the real food you can think of has moisture in it. Now, moisture is a problem if you want something to have a long shelf life, and long shelf life is vital for cost. So there are illusions of wetness in ultraprocessed food. If you think of a moist burger, and there are those famous, there’s lots of instances on social media of people buying burgers from popular burger restaurants and leaving them in their packets and photographing them over a year, and nothing happens. They don’t decompose.
In fact, those burgers, they don’t contain many preservatives. They’re just dry. And dry things, bugs can’t get a grip on dry things. Dry goods don’t decompose. So the dryness, the water isn’t there. They’re very energy-dense because the water should displace energy. They’re drying this off, so we eat them quickly. So we get calories quicker than our bodies can say we’re full.
And remember, we do all have an internal mechanism that is able to say, I am full. There is no obesity in wild animals, and that is not to do with scarcity of food. Many animals live with very plentiful food, but they have homeostatic mechanisms. We all learn, the first thing we all learn in biology is homeostasis. We all have a way of keeping all of our internal physiology the same. Our temperature, our blood pressure, our oxygen levels, our carbon dioxide levels, our blood pH, our sodium, our potassium, we regulate it all tightly.
It would be bizarre if we didn’t do the same for calorie intake, and we can if we eat real food. UPF tells us lies. So there’s sweetness without sugar, but there’s also smoothness without fat.
The Deceptive Flavors of Ultra-Processed Food
So around the 1980s, when fat became the first big molecule to start to be demonized, we replaced all the fat. So we had the evolution of low-fat mayonnaisees. Some of that was just to save money. Some of it was because you can make a health claim. If you can replace a dairy fat with a modified starch or xanthan gum or guar gum, you can actually, if you’re skillful, and the scientists at the food companies are, you can create fatty textures in the mouth, the sliminess of fat, but without any real fat there.
Again, your mouth isn’t just tasting stuff for fun. Taste is an early warning system. So you’ve got bitter tastes, which identify toxins. That’s why most poisonous things are bitter. Most plant toxins are bitter. You’ve got sweet to identify sugar. We think your mouth is able to detect fat, and so if you have a slippery gum but no fat arrives, we think that will be a problem.
And we have savory tastes without protein. So many of you will be familiar with umami. There’s also another savory taste called kukami, and these tastes come from free amino acids and other similar molecules that you get in the mouth, and they taste savory, and they should be present. They’re present in chi, they’re present in ramen broth, they’re present throughout amazing food, and they signal particular nutrition is coming into the body.
When you get the flavor enhancers, the synergistic umami of glutamate, inosinate, and guanylate that you find in huge numbers of potato crisps, when those molecules arrive in the context of potato starch and say real protein never arises, we think that also drives excess consumption. And you may be familiar with some of these products have the once you pop, you can’t stop slogan, and that may be part of what’s driving that. It’s flavored.
UPF has to be flavored because flavor comes from a huge range of different aromatic molecules, and by the time you’ve processed the basic ingredients, they don’t really have flavor, so you have to back add flavor. So the flavoring is a proxy for a lack of phytonutrients. If you look at the number of chemicals in a clove of garlic, say, or any plant, it’s in the many, many thousands. By the time you’ve put that plant, you’ve turned it into, it’s oil, it’s carb, and it’s protein isolate.
The Lack of Phytonutrients in Ultra-Processed Food
There’s none of those molecules left. So flavoring signals a lack of phytonutrients. And UPF affects, this is my daughter, Lyra. Both my kids are, neither of them have engaged with any of this content, by the way, so I do wanna say my kids eat quite a lot of ultra-processed food because food binds us to the people around us. It creates community, and ideally, we would eat real food that connected us to our family and our community in a way that had cultural and historic meaning and would form society. Food is the building block of society.
In the absence of that, I do think it’s important they eat the same food as their friends, that they’re not weird in some way. So my kids do eat some of this, and I’m happy to answer questions about how I feed my kids or how I try and feed my kids. My kids largely feed themselves. It affects the microbiome.
So the particular molecules, neonutritive sweeteners, we think affect the microbiome, and the emulsifiers. So emulsifiers are present in everything from your fizzy drinks to your ice cream to the bread to the ready meals to all the confectionery.
The Effects of Emulsifiers on the Microbiome
They are everywhere. And emulsifiers, as lots of you in this room in scientific training will know, emulsifiers allow you to mix fat and water. And so egg yolk, when you make a mayonnaise, it’s an emulsion made by the use of egg yolk. You can use mustard as well. Emulsion paint is a mix of kind of fatty droplets suspended milk is an emulsion. So emulsifiers occur throughout nature.
You can make an argument that almost every cell in your body is a kind of emulsion. You are an emulsion of aqueous cellular contents with a fatty layer surrounding them. So emulsions in themselves aren’t harmful. But when we study the synthetic emulsifiers, the polysorbate 80, the carboxymethylcellulose, and they work in lots of different ways, it seems like they have very significant effects on the friendly bugs that live inside us.
The friendly bugs have much more agency of the way our bodies work than we previously thought. So we recruit around a trillion bugs. I might be out by an order of magnitude either way there, but we’ve got about around a trillion bugs. They act as a kind of metabolic engine and they help us eat food that we can’t eat. So when we eat fiber, we all know that fiber is good for us.
You can’t actually digest fiber. Fiber is fermented or eaten by the friendly bugs inside you. And they turn it into lots of things, but particularly things called short chain fatty acids that are released into your bloodstream. Some of them nourish your brain. Some of them are good for your heart. Lots of them modulate your immune system.
But this microbiome, you live in a delicate, negotiated balance with it. And if you keep it healthy, it will keep you healthy. It keeps out invaders, it protects the lining of the gut and it controls your immune system. And so mucking around with it seems to be a very bad idea that we’re only just discovering why. As well as its effect on the human body, ultraprocessed food also affects the planet. And so we pay for it many times over.
The Environmental Impact of Ultra-Processed Food
The map there you see is of Brazil and the green lines at the other river, sorry, it’s of South America, at the other river that flows through the Amazon. So there’s a river that we know called the Amazon, flows along the ground. A much greater volume of water flows through the airborne river and it evaporates from trees.
And I’m sure I don’t have to explain to lots of you that rain comes from trees. Rain can’t get very far from the sea. It has to fall on a tree, the tree breathes it out and that’s what carries rain inland. So we’ve now cut down so much of the forest to grow soy that there’s no longer rain falling. And if the rain doesn’t fall, there isn’t even a river you can divert. We’re gonna see desertification.
We’re already seeing water shortages in the soy growing regions. So ironically, the biggest threat to say Brazilian agribusiness is Brazilian agribusiness. The food system that seems to be creating all this food security for us is actually creating enormous instability and food insecurity.
Ultra-processed food and the system that produces it is the second leading cause of emissions and as I say, the leading cause of loss of biodiversity. We pay for it in the lawsuit. You may remember when I was writing the book, my brother, Xand, said to me, wasn’t there a lawsuit where someone sued Pringles because there wasn’t enough potato in it to actually call it a crisp? And I thought, oh, this is a cool story. I’ll write about it. So I looked it up.
And in fact, he got it a bit wrong. It was the manufacturers of Pringles, Procter and Gamble, who got involved in legal action with the treasury. They were the ones trying to say there is not enough potato in a Pringle to justify calling it a potato crisp. And if it’s a potato crisp, it’s a fattable, pay 20% fat, and other crisps, so corn-based chips, for arcane reasons that tax lawyers will explain, corn-based chips and other chips, that you don’t pay tax on.
So it was Pringles suing about their low potato content and trying to claim that it was much more like a sort of extruded cake. This is the homepage of Coca-Cola. This is a global website homepage, just a few weeks ago, at least a few months ago. And you’ll see they’re creating a world without waste. And this kind of homepage is a feature of many of the corporations that make our food.
I mean, there are about 15 companies that make almost all of our calories. In fact, around 75% of our calories come from just six primary producers. They produce most of the world’s grain and oil. So this idea of the companies as cleaner-uppers of plastic, and they almost look like NGOs dedicated to plastic cleanup, is really weird because if you then search the world’s biggest plastic polluter, it is in fact Coca-Cola. So the plastic pollution caused by ultra-processed food is enormous. But the biggest harm, really, is because ultra-processed food is addictive.
The Addictive Nature of Ultra-Processed Food
Now, food addiction for a long time was very unfashionable. It’s problematic because inextricably tangled up with the idea of addiction is the idea of abstinence. You can’t propose something be addictive if you can’t then propose being abstinent from it.
So food addiction for a long time was considered a behavioral addiction. And yet the substance itself, and there will be people in this audience who recognize this in themselves, the substances themselves do feel like the thing that drives the addiction. And the definition is the use of a substance continues despite knowledge of harms, despite repeated attempts to quit.
This is a picture of Lyra eating Cocoa Pops. Lyra can eat, she’s now six, and she can eat five adult portions of Cocoa Pops. If you look at those traffic light labels on Cocoa Pops, you’ll see there are two oranges and two greens. It’s a relatively healthy food. Now, that’s if a grownup eats 30 grams. If a six-year-old eats more than 120 grams, all those lights obviously turn red.
When she’s eating, it’s kind of hilarious, but it’s also as if she’s eating in a trance. So we have a huge amount of evidence that for many people, food is addictive. I’m speaking to lots of senior research psychiatrists about the links between ultra-processed food and binge eating and other eating disorders. This evidence is still very early. It’s really potentially traumatic and sensitizing to talk about. So I say that with caution, but I would say if you recognize that you have an addicted relationship with food, it will almost certainly be ultra-processed products.
And we are working very hard to try and work out how that works and how to quit it. But there’s a lot of different evidence around it. And the reason it’s addictive is because the purpose of ultra-processing is not just profit, it’s financialized growth.
The Financialization of the Food System
So for the book, I spoke to a huge number of different people who work within the food system. The most interesting people to speak to were the bankers, because the bankers understand how everything works. And they explained that the foods, what we think about as a food supply system is actually an inverted money supply system. It’s a way of extracting money from us. Not only a little bit of it to the farmers, but most of it to the intermediary processing companies.
And some of the food companies have made very sincere, concerted efforts to stop selling so many ultra-processed products. Danone have, so Emmanuel Faber at Danone tried to turn it into a social enterprise to really realign the portfolio. Similar efforts happened at Pepsi and at Unilever. In every case, those senior executives were replaced. Activist investors often voted them out.
And BlackRock, the analyst at BlackRock explained this to me, these companies are not in control of their business model. It’s a very small number of institutional investors, owns an integer percentage of all of the companies. And so the purpose of these companies is to provide financial growth for our pensions, to some extent. Certainly my pension, part of my pension is at BlackRock. So I’m very intimately part of the problem.
And so a lot of my research now is trying to use, I’m working with a number of economists now to try and demonstrate that these companies are financialized, that the food system is financialized, that all of the incentives about the way we produce food are financial. And we can show that when public health activist investors put public health proposals to boards and to companies, they’re almost always voted down by hedge funds, by pension funds, and by financial institutional investors. So the companies are trapped inside the incentives.
And so that leads me to a thought of some solutions, but I’m really interested to discuss in more detail with you. I put here the British Nutrition Foundation logo. So this is one of our leading charities that produces information on food. They advise the government, they collaborate with policymakers. And in almost every article that I’ve been quoted in over the last few months, there is someone, a nutritionist, a scientist from the British Nutrition Foundation who also has an opinion on ultra-processed food. Their opinion is, it’s not usually a very useful way of thinking about food.
The reason those food company logos are there is they’re just some of the people who pay the British Nutrition Foundation, which is majority funded by companies that make ultra-processed food. The number one change we need is a cultural change where we come to regard the companies that make our food as being like tobacco companies. Their money is dirty. And if we accept their money, we become part of the marketing division of the companies. And so we need to disentangle all the charities that influence policy from the companies that make the food that is harming us.
We need to put ultra-processed food in our national nutrition guidance. Many, many countries around the world are doing this. So I just came back from New York. I was speaking at the Global Obesity Federation.
Policy Solutions
It’s a UN World Health Organization aligned body. And there is no question in countries around the globe that ultra-processed food is, as I say, the primary cause of diet-related disease, and it needs to be regulated. This is a pack of frosted flakes from Mexico. The tiger is gone, and you can see the black hexagons on the pack. There are marketing restrictions.
And the arguments I make is not anti-capitalist. It’s not anti-growth. It’s not neo-Marxist. It’s all compatible. It all makes sense with really good economic policy. We want to increase choice and freedoms. We don’t want to nanny anyone. I wouldn’t ban this food, and I wouldn’t tax most of it. I mean, we could have some progressive taxes with caution, but in this country, I wouldn’t tax ultra-processed food because it’s the food that we depend on. I’d put the warning labels on.
I’d change institutional food. It’s really good economics to have food in hospitals, prisons, and schools being real food. It’s really important. We’ve got lots of evidence about that. And I’d like to see the rise of not-for-profit food companies. There are pharmaceutical models of this. You can build a competitive company. You can build a company that pays back some investors, in fact, that competes with for-profit companies but isn’t hamstrung by a relationship with those investors.
And there’s an example of the kind of policies we need. In Brazil, we see a U.S. Coke can there, very similar to a U.K. Coke can. In Brazil, the label’s on the back. In Chile, the activists learned the lessons and managed to get the label on the front. And in Argentina, the label is bigger than the logo.
There’s no justification, however you think about food, whether you believe in high-fat salt sugar, and there is value to that classification. There’s no justification for not having a warning label on Fizzy Pop. And there are some foods in Mexico, all the cartoons gone, and warning labels on it. Thank you very much for listening, and I’m happy to take some questions now.
SUGGESTED BOOK FOR READING:
Ultra-Processed People: The Science Behind Food That Isn’t Food
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