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Giles Yeo: Fears about ultra processed foods are just for the chattering classes




Professor Giles Yeo wants you to stop fretting about your supermarket loaf and whether it could be classed as ultra processed food (UPF).

The definition of UPF as something that is made through industrial processes and contains ingredients not normally seen in the average kitchen – such as modified starch or emulsifiers – is too vague to be useful, according to the professor of molecular neuroendocrinology, who will be speaking at the Cambridge Festival this month.

Instead he wants to ensure people who are less well off, who are most likely to have to buy processed foods because they are cheaper, have access to better nutrition.

Professor Giles Yeo. Picture by Scott Chasserot
Professor Giles Yeo. Picture by Scott Chasserot

“UPF is something that the chattering classes can worry and navel gaze about. That’s really my feeling about this. And I think it’s an unhelpful categorisation of food because it’s not precise enough,” says Giles.

He explains: “I think the problem with many ultra processed foods is they are unhealthy because the ultra processing makes them inherently lower in protein or fibre. And they lack flavour, because of the processing, so they have to be made high in sugar, salt, fat to compensate, which is where flavour comes.

“That’s the problem with UPF. But my issue, and what many dieticians also have a problem with, is that the term UPF is such a broad church and a blunt tool it that includes stuff which I think is more unhealthy, and so we should eat less off – such as Turkey Twizzlers – but actually also includes natural yoghurt with a little bit of UPF jam, or the vast majority of supermarket bread. Now, if you think about supermarket bread, taste aside, you and I could go down to our leafy bougie bakery and buy artisanal sourdough and it’s going to taste better.

“But ultimately, bread is made of flour, yeast, salt and water. That’s pretty much it. I mean yes, there might be a little bit of additives here and there in a supermarket loaf, but the bulk of it is made of that. And this is where most of our UPF calories come from. So, aside from it not tasting as good, there is nothing much wrong with most supermarket bread compared to fancy bread, aside from the cost. And this is an example of why I have a problem with UPF – to my mind it is food shaming people because they are eating supermarket bread, telling them you should be having your food from the farmers’ market or something along those lines.”

Look out for fibre and protein when shopping as a guide to healthier food
Look out for fibre and protein when shopping as a guide to healthier food

For the term UPF to be useful when we make decisions about what to eat for our health, Giles would like to see a much tighter definition of what it constitutes. And he wants food companies to try to make cheap food healthier.

“I think there is an overlap of UPF with foods that we should eat less of,” he says. “We need to be more precise in our language about foods. We need to ask: what is the nutritional content? What’s the percentage of protein, how many grams of fibre, how many grams of salt? These are at least numbers and they’re not judgmental because they cover foods that fancy people might buy and foods that poor people might be forced to eat. And then we can have more adult, nuanced, mature discussion about what is healthy and what is not healthy.”

The question is whether these novel foods such as modified starch, sweeteners and emulsifiers, found in foods like ice cream and ready meals, are actually causing ill health or whether it is the high fat and sugar content and lack of protein and fibre that is the problem. It seems evidence is thin on the ground at the moment.

“That it’s something that we need to study and the studies really have not been done,” says Giles.

“There are going to be some breads that are probably not going be good for you because of the overwhelming use of such additives, for example. An emulsifier sounds like a scary thing, but there are naturally occurring emulsifiers. I think that we need to just be more precise with the language and do the science, looking at whether element X, Y or Z is bad for you. Or what is the dose? Because clearly, most things are bad for you at a high enough dose. And so what is the dose that has been used? So I think to my mind, we shouldn’t be scaremongering about food, particularly to people who have no choice about it, so we just need to be more precise.”

Giles Yeo at Addenbrooke's Hospital. Picture: Keith Heppell
Giles Yeo at Addenbrooke's Hospital. Picture: Keith Heppell

In fact, Giles has some very simple rules for anyone who wants to choose foods that are healthier – particularly pre-packaged foods. His discussion at the Cambridge Festival will focus on food quality and why cheaper foods that less well-off people have to eat are damaging their health.

“We need to stop demonising ultra processed foods because many people have very little choice over what they eat,” says Giles.

“At the moment, we live in a world where the healthiest foods are not the cheapest foods, and that is just a sad indictment, I think, of where our food systems are at the moment. As a result, the poorer you are, the less choice you have in life and some people have no choice at all. If you have to eat from food banks for example, then you end up with the poorest quality food.

“Now, how has this happened? People turn around and say ‘Yeah, but beans are cheap and lentils are cheap’, which is true. The problem with a lentil is, first, you’ve got to know how to cook it, and second, people forget that the lentil doesn’t cost a lot of money but it still takes half an hour to an hour on the stove top to cook, whereas if you get something that is premade or pre-wrapped you either don’t have to heat it, or it’s a two-minute buzz in a microwave. And so people do not take into account the whole cycle of the food that’s actually being presented, where food is cheap but requires knowledge and hours to cook.

“If you can buy some prepackaged heavily processed stuff that’s cheaper, because you don’t have to pay for an hour of cooking and it’s more convenient, what are you going to do? And so how do we work with the food system to prevent this from happening?”

He will be in conversation with Nazia Mintz Habib, founder of the Centre for Resilience and Sustainable Development at the University of Cambridge, about the long-term impact of diet and hunger on our physical and mental development at an event for the Cambridge Festival, which begins this week and features hundreds of free events organised.

Cheap food – which many people have to live off due to being time and cash poor – is making the population overweight, Giles warns.

“When you look at the lowest socio- economic classes in the UK, they are more likely to have obesity than be skinny. They are over-nutritioned yet malnourished. I worry about the genetics of the susceptibility to poor diets and why that can actually lead to obesity and Nazia is worried about the macroeconomics and how that influences the quality of food that’s being provided more globally, and so that’s going to be the conversation.

“We’re going to be talking about the quality of food in the world today. And how just throwing calories at the problem is not going to help. We have to improve the nutritional quality of stuff that we give food banks and pallets of food that’s being dropped into Gaza, and just just more broadly. I think we need to think not only about calories but how we improve the nutritional component of all types of food.”

Instead of worrying about whether a food could be classed as ultra processed, Giles says the most important factors are how much fibre and protein it contains.

“Rather than telling people what they shouldn’t eat, I would actually look at what foods people should be focusing on. You need to look at the back of the pack. If you’re buying a frozen lasagne, try and find the frozen lasagna with a bit more protein, with a bit more fibre. I think that’s what the industry should be focusing on.

”Fibre is always going to be vegetables or fruit. That’s where fibre comes from. But if you look at the fibre and or protein content of any pre-packaged food and you compare one class to another – frozen lasagne, chocolate – that is a good shorthand to the quality of the item of food. Poorer quality foods tend to have lower protein and lower fibre. Just those two things are probably enough to ensure that you’re getting a better quality of food.”

The number of calories you eat is much less important that the nutrients your food contains, he adds.

“Calories matter to some degree, but we’re not labelling the quality of the food,” says Giles. “And that’s what we should be trying to do. I’m not talking about just going out and buying carrots because sometimes in life you need a treat, sometimes you want cake, sometimes you want a chocolate bar. I think we need to get to the point where we can make healthier chocolate bars somehow. I’m not saying I have the answers to everything. But I think that we can do better with the food systems and with how we describe foods today.”

Professor Giles Yeo
Professor Giles Yeo

And instead of expecting health changes to be completely driven by personal choice – especially when someone is trying to feed their family on very little money and perhaps without the cash to heat an oven – Giles believes the government should step in to enforce new food regulations.

“I think we do need legislation of some degree. We can’t rely on people voluntarily doing it because companies need to make money. And so they want a level playing field. They want a rule that everyone has to follow. If you make it voluntary, no one’s going to do it because someone’s going to lose out. So we need legislation,” he says.

“But secondly, I also think we need to make sure we engage with the food manufacturers. There is a temptation to demonise manufacturers, which is unhelpful because they make our food. And so my slightly naive, perhaps, view on this is we should make it clear to food manufacturers that if they make food that is healthier for us, that we the consumer will live longer to spend more money with them. I think if market forces make the food healthier, then I think that is a more helpful way of doing it. But in the meantime, we need some legislative push.”

Prof Giles Yeo is speaking at the Cambridge Festival. Hunger: how what we eat – or can’t eat – affects our mental and physical health, 28 March, 6-7pm, Cambridge Union. Visit festival.cam.ac.uk festival.cam.ac.uk to book.



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