Are we what we eat?

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BBC Sounds, Music, Radio, Podcasts.

Hello, we're back for a brand new series.

New episodes will be released weekly.

but if you're in the UK and can't wait, you can hear it all right now before anywhere else.

Isn't that right, Brian Cox?

First, on BBC Sounds, Robin Ince.

That's teamwork, isn't it?

It really is.

Yeah, professional.

Professional.

I'm Robin Inks.

And I'm Brian Cox, and this is the Infinite Monkey Cage.

Today's show is about what you have got in your stomach right now, possibly also in your mouth, and maybe even under your fingernails if you eat your Marzipan without due care and attention.

Or is that an offence now as well?

Yeah, that's where the culture wars have gone now.

They've moved to Marzipan.

Anyway, so we're not just going to be talking about Marzipan, though, we're also going to be talking about spray cheese, cream eggs, Findus crispy pancakes, and toast toppers, all of which our younger producer, Caroline, has never heard of.

She's never heard even of the company Findus.

She is of the bird's eye generation and beyond.

And so for her, it's been like watching an old episode of I Love the 1970s.

I like the boiling bag.

Was it the cod in parsley sauce?

That was my.

Not the butter one.

Do you remember there was a butter one which was

this is great radio, isn't it?

Today, we're asking the question: Are we what we eat?

How has our diet changed over the centuries?

Is the processed food we eat today really less healthy than it was in our grandparents' time?

And what do we really know in a scientific sense about the ideal diet?

And is it true, as many scientists believe, that the next stage of evolution will be that our hands become cylindrical so we can reach the bottom of Pringle's tube without having to tilt it up?

Anyway, today we're joined by a twin with an interest in infectious diseases, a professor with an interest in nutritional epidemiology, and someone who changed from being a doctor to a cake commentator.

And they are.

I'm Dr.

Chris Van Tulliken.

I'm an associate professor at UCL Next Door.

Like most sort of media doctors, I have eventually gravitated toward nutrition.

I've written this book, Ultra Process People.

And my favourite guilty food pleasure is the scotch egg, but the one with the black pudding.

Ooh.

Can I just check?

No, it is like no one knows.

It's not exotic.

Can I just check?

When you say you study at UCL Next Door, do you mean at UCL, which is near here, or do you mean you're in a kind of tribute university called UCL Next Door?

Do I have to answer that question?

No, we'll move on.

Hello, yes, I'm Janet Cade.

I'm professor of nutritional epidemiology and public health at the University of Leeds.

And my guilty food pleasure, well, you already mentioned marzipan.

I didn't know it was a thing, but I like chocolate and particularly chocolate-coated marzipan or those chocolate-coated cherries soaked in Kershaw that you get at Christmas time.

Yeah, they're nice, aren't they?

Follow that, Harry, because they're done very well on that side.

Yes.

I am Harry Hill, and I am also professor of nutritional epidemiology in Leeds.

No, of course, not.

I am a comedian.

And my favourite guiltiest food pleasure is sausages.

And this is our panel.

Looks like you lost your bet there, Brian.

None of them said cannibalism.

Anyway, let's move on.

Janet, we're bombarded with advice about food.

It's everywhere.

But in a scientific sense, so just strictly scientifically speaking, how much do we know about what constitutes a good diet?

We know quite a lot.

There have been lots of studies over many years, years, long-term, large-scale cohort studies, where we can

measure what people have eaten in the past, what diseases they get in the future.

And so we know things like we now have

government eat well guide.

It used to be a plate.

Somehow it's come off the plate.

It's now a guide.

Which tells us that we should have probably the majority of our food fruit and vegetables, about 40% fruit and veg, maybe similar amounts of potatoes and cereals and rice, smaller amounts of protein, but less sugary things, which fruits can be quite sugary, but not dried fruits, not too much oil, not too much salty stuff.

So, and if a pudding?

Yeah.

Yeah, chocolate.

No, no, no, no.

Don't you think those chocolate cherries could be part of your five a day?

Or

not?

Maybe not.

You're the one with the answer.

Whatever you say.

You've been peer-reviewed in the past.

Whatever you say, this audience will accept it.

Yeah, well, they're not.

Let them live the good heart.

Oh, sorry.

Yeah, no, well, I could have, couldn't I?

But they're not really.

Actually, it's still all about balance.

Not too much, enough micronutrients, all those vitamins and minerals, and enough hydration as well.

It sounds kind of obvious and boring, though it's difficult to do because obviously, you know, our needs change throughout the life course.

So actually, to define what is a healthy diet is quite challenging.

Are you saying, as professor of nutritional epidemiology, that a little of what you fancy does you good?

I don't want to put words in your mouth, Jack.

That is, broadly speaking.

So it's essentially an in moderation.

You listed virtually every

in moderation.

I think so.

I think that's the answer, isn't it?

What we've done is we've swamped ourselves with high-energy density food products that we want to eat more and more of.

So it's about having that restraint, perhaps, moderation, making sure we have enough fibre in our diets, because I think that's one thing that we're all quite short of.

We need to eat more dietary fibre.

By doing that, you reduce your energy density.

So you're eating less calories and not gaining that weight that you might do otherwise.

Chris, now, for a lot of people,

they know you're both for Operation Ouch and also for an area of expertise is infectious diseases.

But you are now increasingly, as you mentioned as well, the book that you've written is such a

you're fascinated in nutrition.

When did that start?

When did you become that interested in nutrition?

So I came there through an odd route because I'm an infectious diseases doctor.

I've done a lot of global health where I've worked in very low-income countries.

And we see that the malnutrition caused by the food industry marketing foods, harmful foods, very aggressively to people who don't have clean water, who don't have the capacity to store them or make them up properly, causes malnutrition that leads to infections.

So, working in

countries where people don't have enough money creates an interest in the food that supports our immune system and supports our health.

So, that's the background to how an infectious diseases doctor comes to be interested in.

I was interested as well because there's a big exhibition at the moment in London at the Wellcome Collection all about milk.

And and it seems like the story hasn't changed in a very long time because there was a big poster and it was all about how condensed milk was something which people in poverty were often using as an alternative to breast milk and that was creating malnutrition.

And from you know, reading some of your books, that seems to be still the issue, 80 years on.

Infant food is a really

ticklish thing to talk about because it's incredibly stigmatized because everyone feels very wed to how they fed their children.

And we feed our children according to the food that's available in the society we live in.

We have really an emergency about child health, particularly, where one in five children

are leaving primary school with obesity.

And it's nothing to do with their fault.

These are diseases caused by an industry that is aggressively marketing foods that, as Janet says, are really, really hard to stop eating and that interfere with our evolved mechanisms that tell us we've had enough.

See, I was going to talk about Junior Bake Off, but I don't know how to say it.

Oh, I think there's a very easy segue here.

I think it's very simple, which is, Harry, we've just been talking about children and too much sugar.

You force children to eat cakes on television, don't you?

Do you feel like maybe you're the bad man?

Listen, if they die, they die.

They know what they're getting into when they join up.

Okay.

It's true, though.

I mean, as a kid, when I was at school, when I was like in the 70s, every school just was allowed one obese kid, wasn't there?

There was one fat kid, he was called donut, and he had a briefcase full of crisps.

I mean,

and his mum claimed it was a glandular problem, but now they're everywhere.

And this is the subject of today's show.

The attitude to food has changed.

Like I say, when I was a kid, you wouldn't think to take a photograph of your lunch and put it on, you know, and

show it to someone because basically food was so horrible back then you wanted to forget about it.

And the other thought I had about your, you were saying about what's a good food and a bad food.

Surely,

yeah, okay, great, eat a lot of blueberries, but you know, if they're out of season, then they're being flown in from, I don't know, somewhere, and that's bad for the environment.

You know, it goes beyond what you're eating, surely, doesn't it?

Yeah, I mean, we definitely need to consider not only nutritional aspects but sustainability metrics too.

So, I mean, who knows how bad for the environment our diet is at the moment?

We're still finding that sort of thing out.

Because everyone always talks about the Mediterranean diet being good for you, but you know, if you live in the Mediterranean, you can eat that stuff, but over here, you've got to

fly in.

Even now, you know, Mediterranean diets changed over the last 50 years or so.

So, what's been talked of as a Mediterranean diet, plant-based, small amounts of good quality red meat, a bit of red wine, olive oil and so on, people living in the Mediterranean now aren't eating diets like that anymore, which were the things that were helping people to perhaps live a bit longer.

So, yeah.

That idea of the Mediterranean diet, as you mentioned, it's 50 years ago, there was a specific diet.

The first question I asked was about the evidence, what we know.

Wasn't that historically one of the first big studies about nutrition?

Yes,

there have been been

early days, I suppose, was Mediterranean diet, and that linked through to low-fat diets as well.

But some of that, I think, links to the industry perspective and the low-fat diet then that followed on from the Mediterranean diet was really being promoted by American senators who maybe had a family history of heart disease.

And even before all of that, if I could take you back in time to the Boer War, I had to look up that actually, how to pronounce Boer?

Boer War.

The Boer War was a battle between strippers and drag acts.

Okay, so what am I saying?

Boar.

The Boer War.

The Boer War.

The Boer War.

So the Boer War was actually, I think, the birth of nutrition as we know it today.

And it came about because the conscripts going to war were malnourished.

And so everyone was very worried about that.

The medical fraternity were a bit up in arms and published something in the British Medical Journal, which in 1903 said if parents' earnings were insufficient to provide an adequate diet, it was easily conceivable that the British race would deteriorate.

Now, whilst I don't like the idea of British race, but nevertheless, we could be hearing those words today, couldn't we?

If parents' earnings were insufficient to provide an adequate diet, you know, children are going to be malnourished.

That's what what you were saying, Chris.

And I mean, this is this is profoundly true in 21st century Britain, in 2023, that if you are in the lowest 10% of households by income, you would have to spend almost all your money to eat according to the NHS guidance to eat a healthy diet.

So you wouldn't have any money left for your rent, for your energy, for your fuel.

So this sort of food apartheid that we live in is a huge problem where people simply don't have enough money to eat well.

So this is, it's interesting to me because a lot of the way this can get talked about is, oh, it's because people eat junk food, it's because people don't, but if we're talking about a hundred years ago, we're talking about, you know, we've been talking about 200, you know, this seems to be again, it's it's perhaps the contents of the story change, but the story itself doesn't seem to change.

I think there is

a sort of national understanding that people have a personal responsibility for what they eat.

And there's a lack of understanding that actually we just eat the food that we can afford and that's presented to us.

And at the moment, we're surrounded by food that's extremely hard to stop eating, and much of it is sold to us as food that's healthy.

So, we have this classification now of ultra-processed food, which now makes up more than half of our diet.

It's about 60% of what we eat.

And there's a long formal scientific definition, but it boils down to food that's wrapped in plastic and it contains an ingredient you don't find in your kitchen.

So, just going to processed food, first of all.

So, processed food, what would that be?

For people today, Brian today had a chicken curry pie for his lunch, and that's true.

It's what he had.

It was the only pie left.

He was quite cross about it.

It was either that or a vegan pie, and he won't eat anything unless something's been killed.

He has no emotional heart.

Are you his carer?

He just had that look about him.

What would be a processed food then?

What was the...

Well, if we think about milk, milk's quite a good example.

Whole milk, you can drink it straight out of the cow.

It's just a whole food.

We can process it and turn it into traditional foods, cheese, butter.

And we've been making cheese and butter for six, seven thousand years.

We don't think those foods are associated with diet-related disease.

We don't think they cause early death.

Or we can ultra-process it, where we can separate the milk into its fats and use them for something else, and then we can make low-fat yogurts with modified maize starches and artificial flavorings and artificial sweeteners.

And those foods have been ultra-processed, and we think that that category of food is associated with weight gain, partly because they are engineered to drive excess consumption.

I mean, that is the purpose of most of the packaged foods that we eat today.

And

they're not hard to stop eating by accident.

They're hard to stop eating because they're meant to be hard to stop eating.

Janet, I mean, that sounds quite kind of Machiavellian.

But is it specifically designed like that, or is it more, hang on a minute, this is selling really well, let's make more of this?

So it's not quite as pre-planned as it might look.

I don't know about pre-planned, but what I do know is that those foods tend to be very energy dense and they're easy to eat, and you eat them more quickly than if you were having to choose something which had a lot of fibre in it.

So you're going to eat more of it.

So whilst the processing may be an element, it may not be an element.

It may just be what's in the food, the nutrients.

So too much energy, you're eating it quickly, it's soft and pappy, it's easy to just shovel in and keep shoveling in.

It tastes nice.

Taste must play some role in this.

Taste does.

You know, taste is a whole other interesting area.

Babies, when they're born, one of the first things they do like is that sweet taste too.

They're drawn to that and will eat sweet foods.

So we're kind of programmed for that.

Janet, when did you...

I mean, you're involved in a panel looking at the toxicity of food.

So I would imagine in the 16th century, you would have just been someone who walked through woods and told people not to eat those berries.

Whereas now...

That's your view of a professor of nutrition.

To be honest,

science in the 16th century was not great, Brian, okay?

Seen that wig that Isaac Newton wore?

That's not an intelligent man's wig.

Can I give you a story about the first controlled trial?

Actually, nutrition has a great history in that the very first controlled trial was of foods and nutrients.

A captain James Lind in 1747 noticed that all the sailors on long-haul journeys were dying and dying of scurvy.

They didn't know what was causing that.

As we know today, it's lack of vitamin C.

And so he allocated different groups of sailors to receive different things.

Some had to eat seawater, others various things, including some with the sort of citrus fruits.

And they were the ones that survived.

So actually, whilst you might say, you know, someone wandering along saying, don't Don't eat this, do eat that, that's kind of how it happened.

You could have had cider or nutmeg as well.

They were two other options.

Cider or nutmeg?

Yeah, it was a various different, I'm not sure.

Obviously, it was before my time, actually.

Yeah.

So, that's when we begin to see nutrition as, I suppose, as a science.

We were driven to it by the necessity to keep people alive on long sea voyages, essentially.

Yeah.

And how does the science then develop?

I mean, today, as you said in the introduction, it's complex, and it's

understanding what an ideal diet is,

is a very complex question.

So, what are the landmarks if we go through the history of nutritional science?

So, you know, when I grew up, for example, people would, I remember it vividly.

It was don't eat saturated fat.

It was certainly in the 70s and 80s, saturated fat is an evil thing, and do not eat it.

But now,

that seems to have changed somewhat, and saturated fats are not

the demon that they were made out to be.

That's right, they're not.

The evidence wasn't there for saturated fat when they actually looked and did some randomised control trials testing saturated fat versus other types of fat and

lower fat, and they just didn't find the evidence that that was associated with increased risk of heart disease.

So, yeah.

Is it okay to eat butter and cream then?

Yes.

Oh, no.

Yeah.

All these lost years.

I remember thinking thinking at the time, you know, everyone was eating margarine in the 70s, wasn't it?

I remember finding out how it was made.

It's like

sunflower oil passed over, I think it was an aluminium catalyst.

And I thought, how can that be good for you?

Yeah, because it was.

It was unsaturated, high in unsaturated fats, wasn't it?

It was a marketing.

Very much so, yeah.

Which I remember.

And then it obviously was followed with things like the Atkins diet, the

very low-carbohydrate diet to treat obesity.

But actually, again, that's been, I would say, discredited.

It's really, it's neither low-fat nor low-carbohydrate.

It is the simple message about how much energy.

And then, if we think about physical activity levels, that's gone down.

So, actually, overall, our energy intake needs to come down.

So, by energy, you just mean it's what you read as calories.

Calories are very good.

Exactly, I do, yeah.

Yeah, it doesn't matter where it's coming from, it's total calories.

Which is interesting, isn't it?

Because

today we hear lots of messages about this: this is this food is good for you, this food is bad for you, this food don't eat as many carbohydrates or whatever it is because it turns into sugar.

But essentially, you're saying that the bottom line, first and foremost, is how many calories are you ingesting per day relative to how much you expand.

It's conservation of energy, basically.

And whilst it's being marketed at us, even so, I suppose I'm interested in measuring that.

You know, which of us here knows how many calories we've consumed already today?

I don't.

So, unless we try and get a handle on that and measure that, not every day, I'm not suggesting.

I've got a theory.

I would like it to become as common for us as children to kind of take a check on what we're eating as we go to the dentist.

We're always going to the dentist, you know, here, teeth.

Why don't we think about what's going past our teeth?

And luckily, today we have got some tools available to us that help us to do that.

Back in, you know, when I started, it was still bits of pencil and paper where you had to write it down and use books and stuff.

But now we've got apps we can use, and perhaps people have used some of those.

And in fact, everything has changed, and we need to be able to measure what we're eating better.

So, so, so, it's just about the calories.

So, junior bake-up is not morally abhorrent

as long as you eat small cakes.

Is it about the quality of the calories, though?

So, is it okay to eat the same amount of calories if it's a Mars bar or if it's, you know, because there's this sort of

what you're saying about the process, isn't it?

Well, Janice's absolutely right that,

unsurprisingly, for a professor of nutritional epidemiology, let me add my voice to hers.

It really is about calories.

A calorie of Mars bar is exactly the same as a calorie of Junior Bake Off poison cake or

a calorie of celery.

The difficulty is that some of those calories are quite easy to stop eating.

So, animals, for example, obesity is essentially unknown in wild animals.

It simply never happens.

But

wild animals don't have labels that they look at, and they are able to juggle their food very precisely.

And they're not just a healthy weight because of deficiency, because there isn't enough food around, or because they burn more calories.

They have very well-evolved mechanisms that tell them when they need to eat and when to stop.

And we have those mechanisms.

There are some fat dogs about.

Yeah.

Wild, wild animals.

So wild, wild animals.

Definitely pets and urban, some urban animals.

There is a beast here now.

Manatees.

Manatees, there are manatees.

So in fact, manatees...

Don't they need that lubber?

No,

if you look at humans, the average UK adult human has approximately the same percentage of body fat as a sea mammal.

So as a whale or a walrus or a dugong or a manner.

So

humans in modern Britain have incredible amounts of adipose tissue.

And we have these mechanisms, but the point about some of the foods that you talked about, Harry, without mentioning any brands, is that they subvert these mechanisms.

So whilst you can eat a calorie of your chocolate bar,

you may be driven to eat another one of those calories and another.

So the problem is humans don't eat very well to labels.

We've got internal mechanisms that should guide us, but if we don't eat foods that we've been eating traditionally, those mechanisms don't work particularly.

So, if you, for example, decided you'd eat the so-so, a Mars bar has however many calories, kilo-calories, I should say.

Oh, there always offenses are available.

Kilo calories.

Anyway, kilojoules.

Kilojoules, yeah.

But if you try to eat the same amount of calories in celery, for example, you'd get bored.

You would.

You wouldn't eat it.

It would be a vast amount.

You'd never get anything else done, would you?

I thought

I had one idea to kind of cure the obesity epidemic, would be to make narrower doors

so people couldn't get out.

When they got to a certain size, they wouldn't be able to get out and get any more food.

You're forgetting delivery services, Harry.

I'm afraid that happens, doesn't it?

How cunning you are.

So, going back to

how we know these things, so you mentioned randomized trials, which is clearly difficult to do,

and that's some of your research.

But, in terms of the response of the body to certain foods,

how much do we know about that physiologically?

Is that part of the research?

Where you say, well, we understand how a certain amount of whatever it is, saturated fats or something, how that's metabolized.

Does that matter at all?

Is that important?

I think it is important.

It helps us to get another handle on, you know, are we good enough with measuring what's going in?

But we don't have good biomarkers for most nutrients.

Actually, it's extremely difficult to do.

So, and usually involves taking blood samples or urine, which people don't want to provide.

So, we don't have a lot of knowledge.

We do know things like fatty liver is increasing, but again, to actually measure that without doing some intensive investigations is hard.

So,

we don't know as much as we should, I think, about the physiology behind all of this.

And that's usually done in very small-scale studies, not these bigger population-based ones.

I mean, Brian, you mentioned this idea that in the seventies and the early eighties, fat became the demon.

Then in around two thousand, sugar replaced fat as the demon nutrient.

And a huge effort was spent trying to work out if we eat one calorie of sugar, is it worse for us than a calorie of fat in terms of its capacity to drive weight gain?

And there were these theories that it spiked your insulin and changed your basal metabolic rate.

And at the end of, I would say, what, 15 years of quite intensive research, we're pretty sure, we're about as sure as we are of anything in nutrition, that a calorie of sugar is the same as a calorie of complex carbohydrate, or a calorie of fat, or a calorie of protein.

They all have an equal capacity to allow you to gain weight.

That's really surprising, actually, isn't it?

It is just counterintuitive.

Have you told anyone else about this?

I've been thinking

I should go on the radio talk about it.

But I can't find a platform.

I've been following that bloke.

My wife and I have started on that

Michael Mosley.

Is it not Max Mosley?

Michael Mosley.

Certainly not Oswald Mosley.

My nemesis.

Is he your nemesis?

No, he's not.

Yeah, but he has this theory about, isn't it?

It's about, you know, more complex carbohydrates are better for you than simple ones.

Isn't it?

I mean, that's one of the sort of things.

Well, that's a slightly different question.

So if you eat complex carbohydrates, they may well satiate you more, and you might eat fewer of them.

But that's not the same.

Calorie per calorie is the question that the scientists, many of whom are ex-physicists, actually, so the physicists really got into this, the nitty-gritty of this question and solved it at a cost of about $50 million.

A couple of them.

That's what we do.

It was a huge thing.

How are we going to work it out?

We're going to send carrots and masbars underneath Switzerland at speeds near that of light.

We can do it, no.

I mean, at the end of the the argument between these two pretty eminent physicists about these molecules, we were still left in the midst of a growing obesity pandemic because, of course, it had diverted attention, the row about fat versus sugar, diverted attention away from the fact that we're being aggressively marketed these foods that are impossible to stop eating, the ultra-processed foods.

So, in a sense,

there was a big distraction going on with the argument about the macromolecules, when actually we should be focusing on the marketing and the way the food is packaged and sold to us.

But

the answer to aggressive marketing and a perceived baddie is normally to increase the price of this stuff or to ban it or to put a health warning on it.

Is that what you're saying?

Well, no, I think that thank you for serving me up that low ball, and I'm sure Janet will have a view on it.

However, we think about the modern food that makes us sick, whether we think of it as high-fat salt sugar or we think of it as ultra-processed, this is essential food for people with low incomes.

And you cannot ban it.

You don't want to do anything to increase stigma, you can't tax it.

And so, you have to handle this discussion with incredible sort of nuance and sensitivity, as you've been doing, Harry.

When we get our letter of complaint from Donut, we are going to be in such trouble.

I was going to say, because your solution was to pass a law that only allows one fat kid per class, as far as the remote.

So, you know, the option is very sensitive.

It's like marketing bans or joinery regulations.

You know,

that's the way we're heading.

So, reformulation might be an option, I suppose, where we improve the quality, nutritional quality of.

What about stigma though?

Increasing stigma.

Well it's I mean

just saying that wouldn't work.

What we know, I mean to answer that correctly to engage with that really seriously is we know when we increase stigma it drives weight gain and that that

there is no individual characteristic that drives more stigma when it comes to people's interaction with doctors than than living with overweight or obesity.

And I think one of the first things we need to do is change the language we use: that people live with overweight and they live with obesity.

They are not obese, it's not an identity.

And doctors, in particular, healthcare professionals, judge people who live with those conditions more harshly than they do because of income or race or any other personal characteristic.

So part of the thing we need to deal with is

this is not an issue of personal responsibility.

This is a failure of government.

It's a failure of the medical profession to regulate the corporations that make us fat.

There must be a component of knowledge because,

as we've discussed,

those messages that tend to be embedded, I mean, for us in our childhood, as we discussed, I instinctively think that saturated fat is bad because it was drummed into my mind, kind of some is in the subconscious somewhere.

So, how much of this is about providing that information?

And it must be difficult, a follow-up question, because as we've said, it's extremely complicated.

Or is it or is it just as simple as saying calories in, keep them at a certain level?

I think we need we do need education as well.

And that's why I was saying, you know, I think if we if knowing about what you eat was more entrenched within the national curriculum, and then people were just able, kids were able to say, yeah, that's what I had, and oh, that was learned.

You can see the distribution of the class.

I know it's not answering every part of it,

but at least it starts to normalize what is a very normal thing to do, which is eating.

Knowledge is also about sort of counter-information.

So, we have a chocolate-coated rice puff cereal at home for breakfast, and my five-year-old enjoys it.

And the box says that it's a good cup of colour.

We have good soccer pups.

So,

the box is intended for my five-year-old daughter because it's got a monkey on it.

And the labelling says it's a good source of vitamins, it's got reduced sugar, and the traffic lights, the little labels, are orange and green.

So, this is a healthy cereal.

The problem is that my five-year-old eats four adult portions for breakfast.

And people say, oh, well, you know, that's bad parenting.

Well, anyone is welcome to come to my household at seven in the morning and negotiate with Lyra, but

you know, that's not a hill I'm going to die on.

So

the difficulty is that when you're supplying this information, you're supplying it against the information that's on the packages.

So when we talk about people's right to knowledge, it should include their right to be free from misinformation.

And I think the problem is a lot of the foods that harm us are sold as healthy, as life-giving, as important for our health, as promoting weight loss.

And actually, they're probably driving significant rates of disease.

I suppose it is quite natural, isn't it?

If you see something that is a health food or sold as a health food, you might think, Well, so I can eat a lot of that and it's a healthy thing to do.

But as you say, ultimately, it's the portion size and how many calories in that portion that you can eat that's the real issue.

Yeah, we've been doing a lot of work for WHO on baby food, weaning food.

And whilst there are controls on what you can advertise to children, TV Times, there was nothing for babies.

And we know that, you know, the products that are made for babies, for weaning,

have all sorts of claims on them and describe themselves in all sorts of ways that doesn't actually reflect what's in there.

So it starts right from day one, really, what you know, that information or potentially misinformation so yeah we need to improve on that i wanted to just ask actually chris because we we can't you know one of the interesting one of the many interesting things about you is that you have a twin brother and so you have been able to do you know twin studies are quite hard sometimes to get through uh you know kind of the the the ethics committee but you've had experiences where you a bit like Scott Kelly and his brother, twin astronauts, that you can have different perspectives because you are in different positions, different diets, and you can see how they affect you.

Yes, my brother went to work in the States for 10 years and he went there in quite stressful circumstances.

He had a new son in an unplanned way.

It's very happy now, but it was stressful at the time.

And he gained over a short period of time an enormous quantity of weight.

And we have the same genes.

We have the same genetic vulnerability to obesity.

We both carry all the genetic markers that put us at risk of that.

And so when he moved to the States, he put himself in this new food environment.

And that food environment, where food is incredibly aggressively aggressively marketed led to this weight gain.

So, yeah, twins are a really good natural experiment that demonstrate that

people in America are more likely to gain weight.

Arguably, other people had shown that in different ways, but it was nice to add to the body of data.

It's interesting what you say there, though, because we've talked about just this simple equation at the base level is the amount of calories you eat.

So, what are the genetic markers that you refer to?

So, I mean,

I suppose the question is: if you had two people just selected at random from the population and fed them the same thing,

presumably you'd have the same outcome.

You would, and that is

such an important keystone in the argument that obesity has nothing to do with willpower, because all of the genes that affect our propensity to gain weight are all expressed in the brain.

So they're all about eating behaviours.

And people will be able to tell if they have any of these genetic risk factors because they will find themselves highly motivated by food.

And we all know people who are somewhat indifferent to lunch and can skip dinner.

Those of us with these risk factors are obsessed with food, we're prone to, you know, we'll plan dinner at breakfast time and we'll be foodies.

And so that's how you can tell.

And that what willpower is, in a way?

Well,

I mean, willpower.

No, because you're born with this sort of innate drive toward food.

But the really interesting thing is that the way you inherit those genes, the way they're expressed, is entirely dependent on your family income.

So obesity is heritable in low-income populations, and this was all sorted out with twin studies.

The same genes are not expressed.

So, in high-income families, we don't see obesity being inherited.

And that's because people who live in places with lots of money and have access to good food are much less likely to gain weight.

So, we see what the twin studies really tell us is that if we could get rid of inequality and get rid of poverty, we would deal with well over half of the problem of diet-related disease and obesity.

Interestingly, I think it's interesting.

Guide dogs that are most successful are the ones that express some of those desperate needs to eat all the time, so they can really be trained to that treat.

So,

highly motivated, so you can teach them exactly what to eat.

Exactly, yeah, to eat.

Highly motivated to eat.

I'm very trainable, too.

I mean, I'll do anything for a biscuit, you know.

I just wanted to say, are there other factors that we can all pay attention to beyond the food that we eat in order to be healthy?

The really interesting thing is that what we're increasingly sure about is that when you do lots of exercise, you don't burn more calories.

And in fact, we've been studying this for a very long time using quite sophisticated double water labeled methods.

And so when we talk about this energy balance, what we're more and more sure about is that while inactivity is very harmful, activity, if you do lots and lots of activity in your day, it doesn't increase your total calorie burn.

It just takes from your calorie budget, which is the same in everyone.

Surely, if you run a marathon,

then you will burn more calories than if you sit down and watch someone else running the marathon.

So that is true while you're running the marathon.

But if we study people over a long period of time, what it seems is that if you, instead of doing essentially a sedentary job in the UK being a physicist and broadcaster, if you move to become...

I have to climb up a lot of mountains.

He does not do it.

He is in lowered onto them.

An advert for Solvite, I can tell you.

I presented Telly.

What you're saying is that you're

averaged over a week or a month, even if you're an athlete or someone who trains quite a lot.

Right, your calories are determined by your sex, your age, and your body composition.

And if you go and become a subsistence farmer or a hunter-gatherer or a miner, your calories per day will not change.

You'll just spend your calories in a very different way.

So you can go and do your marathon, but you spend your downtime burning fewer calories than when you're running.

And we're really sure of this.

So the whole idea that when you look at your little watch and it says, oh, you've burned some calories and you've burned 350 calories in a treadmill, that you can then go and eat, you know, one of Harry's bars, it's not my

bars.

Are you saying, do less and eat more butter?

That is very much the message of the show

and the title of my next book.

Can I just put a shout out for fidgeting?

Because we've done some work which shows that if you're sedentary, that's not good for you.

But if you are sedentary and fidget, then actually that does reduce your risk of long-term

ill health.

You're the most fidgety person, I know.

And I tell you what, I put that in our study 20 years ago because my husband was very thin and fidgeted all the time.

He now is not so thin and doesn't fidget half as much.

But we asked a question about fidgeting and if you're sedentary but fidget, that seems to help.

I don't know if you can make yourself fidget.

Fleas.

Fleas is what we want.

Bottles of fleas that you get in the supermarket.

Fleas and butter.

That's what the whole message of the show is.

So Harry, I'd like to know, because we've reached the end now, and it's,

you know, how much do you feel we've changed your life from this show today?

I feel more confused.

I mean, that is astonishing to me that, you know, if you do a lot of exercise, actually, your spare time is

still very good for you because...

Well,

what does that mean?

How can it work for you?

Well, so if you're so

cardiovascular.

I'm burning 2,500 calories a day, roughly, every day of my life.

And either I can go for a run and spend some of those calories, or I can sit at my desk and I will then have to spend those calories, like the council road budget, and I will spend them on anxiety, on inflammation and on reproductive hormone elevation.

And if you go for the run you stop yourself burning the calories on all those things that we know are harmful.

So it helps explain why exercise is so good for us, which we know it is, but it also explains why we've never ever found that exercise helps people lose weight.

And it really doesn't.

There's loads of data on that.

But you'll live longer.

You will live longer if you do lots of activity in exercise.

Yeah, with Janet?

Yes, I do agree.

Although you're going to end up with permanent injuries, you'll do your your knee in.

This is not the permanent.

I love this.

This is the best show we've ever done.

A fidgety man who loves eating small yogurts has never been happier, Harry.

Now, we also asked the audience a question today, and we asked them: if you could make one food truly wholesome, what would it be and why?

What have you got, Brian?

Strawberries dead or alive.

Excellent.

Let me process this question.

Oh, yes.

Processed food.

Swiss cheese, because it has some holes in it.

And would be much better if it were wholesome.

Turkey Twizzlers, so I can prove Jamie Oliver wrong.

That's from Cameron, who's in two seats.

Thank you very much, Harry.

Thank you to our panel there.

Harry Hill, Janet Caden, Chris Van Tuliken.

On next week's show,

we are dealing with super volcanoes, which means just a lengthy selection of anecdotes from Brian about all of the volcanoes.

Tell us one of your volcano stories while I read most of Crime and Punishment.

Funny thing happened to me on Volcano.

Thank you.

Bye-bye.

Hello, my name's Michelle DeSwort and I'm Laura Smith and we have a new podcast from BBC Radio 4.

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