Dr Chris van Tulleken: Why I’ve given up ultra-processed food
The TV doctor has lost weight, sleeps better and aches less since spurning so much as a squirt of ketchup. Non-natural foods should be treated like cigarettes, he warns
On one wall of Dr Chris van Tulleken’s kitchen (next to “Daddy’s cursing chart”) there is a magnetic whiteboard with a list of the week’s family meals: lasagne on Monday, then broccoli pasta, followed by chicken. So far, so good. Then comes Friday: fish fingers and oven chips. Fine for Van Tulleken’s wife Dinah and their daughters Lyra, five, and Sasha, two, but not for him.
Since researching his new book, Ultra-Processed People, the 44-year-old TV doctor and associate professor at UCL has entirely given up ultra-processed foods (UPF). For the past three months, not even a squirt of ketchup has passed his lips, nor have the Pret sandwiches and high-end ready meals that used to form part of his regular diet. His twin brother Xand, the other half of the TV medical double act best known for their BBC children’s show Operation Ouch!, has done the same.
“Clothes are looser, I can run better, I ache less, I sleep way better — because I’m less full of salt and I’m less full — and my mood is better,” says Chris, the younger by seven minutes, and a doctor of infectious diseases at UCLH and the Hospital for Tropical Diseases. “I don’t know if that’s because I’m not consuming artificial colours and additives and emulsifiers, so my microbiome is healthier — or it’s just that I’m no longer constipated, I don’t have piles so my bum doesn’t itch and I’ve had a good night’s sleep!”
Van Tulleken has lost 4kg, but he feels uneasy celebrating it given that many people could not afford to give up UPF. “I’m very privileged to be able to give it up — I can afford to replace my sliced bread with bakery sourdough, for example.” Even if you can afford it, it’s a difficult choice because we live in a culture surrounded by the stuff; he compares it to smoking in the 1950s: “Everyone around you was smoking — it would have been nearly impossible to quit.”
Van Tulleken is at pains to say that abstinence is not for everyone. Dinah, who is a fashion editor, and the children eat occasional ready meals and ice cream, although sliced bread and breakfast cereals have been swapped for bakery bread and porridge.
But he would like us to think a bit. The average person in the UK gets nearly 60 per cent of their calories from UPF. For one in five — including teenagers from all socio-economic backgrounds — it is more like 80 per cent. When he totted up his own intake in 2020 for a documentary, it was 30 per cent.
“The fact that I was eating 30 per cent — and I’m a physician — sums up the problem. We are all now saturated in this.” He says food companies are increasingly targeting higher-income customers who might never eat a Turkey Twizzler but would happily pick up an ‘artisan’ microwave lasagne or wholegrain seven-seed sliced loaf. “We are seeing this enormous growth of the kinds of things I was buying — the fancy supermarket breads, the muesli, the handmade ravioli that’s so affordable you can eat it every night.”
The manufacturers’ aim is to create convenient, appealing food with a long shelf life, which is cheap, he says. “It’s about driving excess consumption, creating products that are this perfect synthesis of addictive qualities.”
Van Tulleken hopes that his explanations of how some of these foods are made will help to put people off them. It worked for his brother Xand, who after moving to the United States to study in his early thirties had put on more than 40kg (six and a half stone). In 2020 he had heart surgery after developing complications of Covid-19, which both brothers believe was due to his weight. Since reading a draft of the book he’s lost 20kg over the past four months, and looks the same as Chris for the first time in years.
The ingredients of UPF products, he explains, are often a protein, fat or carbohydrate extracted (“fractioned”) from a cheap crop grown for animal food, like soy or corn, which is then further modified. “Our calories increasingly come from modified starches, from invert sugars, hydrolysed protein isolates and seed oils that have been refined, bleached, deodorised, hydrogenated and interesterified [a process of rearranging fatty acids at a molecular level]. “These calories have been assembled into concoctions using other molecules that our senses have never been exposed to: synthetic emulsifiers, low-calorie sweeteners, stabilising gums, humectants, colour stabilisers, carbonating agents, firming agents and bulking — and anti-bulking — agents.”
Pastries, pies, fried chicken and sauces all started out as real food, he says. “But the non-UPF versions are expensive, so their traditional ingredients are replaced with cheap, sometimes entirely synthetic, alternatives. New substances are being tested on all of us all the time to see which of them is best at extracting money. Can a synthetic emulsifier be used instead of an egg? Can a seed oil replace a dairy fat?”
Low-fat and low-calorie products are a particular con, he says. “Replacing dairy fat with modified corn starch — which gives that creamy mouth-feel — costs possibly 100 times less per gram. It’s a double win for the company — they can sell it as a health product and they’re saving money on the sugar.”
Modified starches have been used in food since the 1930s but the crucial difference then was that most diets were still mainly based on home-cooked food, he says. Even in the 1980s a UK diet was nearly 60 per cent fresh. Now it is the reverse and many believe the growth of UPF is behind the obesity epidemic.
Van Tulleken set out to prove this in 2020, by eating an 80 per cent UPF diet for one month for a BBC documentary. For four weeks he ate cereals, ready meals, takeaways and soft drinks, and put on more than 6kg. The diet made him feel tired, sluggish and anxious, and he developed heartburn, constipation and piles. An MRI scan showed increased connections in the areas of the brain involved in the desire for food, and the reward received for consuming it.
“The evidence is very clear that this food is the leading cause of early death on planet Earth. It increases your risk of Crohn’s disease, metabolic disease, strokes, heart attacks and dementia,” he says, flatly.
The spongy softness of ultra-processed bread encourages faster and greater consumption, as it is absorbed so quickly that satiety hormones do not have time to be released
Van Tulleken concedes that we do not know what exactly it is about UPF that is so bad: is it simply that it is high in salt and sugar, which are known to drive over-consumption? Scientists, he says, now suspect it is more than that. At the National Institutes of Health in the US, Dr Kevin Hall, a researcher, gave one group an 80 per cent UPF diet and the other a non-UPF diet — both of which contained the same amounts of fat, sugar, salt, fibre and calories. Subjects could eat as much or as little of the presented food as they wished and the UPF group ate 500 more calories a day.
Part of the answer could be the destruction of the “food matrix”, the natural structure of foods, by processing. A lot of UPF has a spongy softness so it, (think sliced bread) and you gobble it down quickly. “The signals that tell you to ‘stop eating’ haven’t evolved to handle food this soft and easily digested,” he explains. “Rather than being digested slowly along the length of the intestine in a way that stimulates the release of satiety hormones, it may be that UPF is absorbed so quickly that it doesn’t reach the parts of the gut that send the ‘stop eating’ signal to the brain.” It has been suggested that the lack of chewing could explain why in the UK and US, about a third of 12-year-olds have an overbite — a lower jaw that is too small for their face.
UPF is also dry (which helps to extend its shelf life), making it calorie-dense. “In Hall’s experiment, the softness plus the calorie density meant that participants consumed an average of 17 calories per minute more when eating UPF,” says Van Tulleken.
Or could the main risk come from particular ingredients? He is quite persuaded by the theory that emulsifiers (present in pretty much all packaged bread) could single-handedly be behind global obesity. In 2015, a team from the US and Israel experimented on mice with two commonly used emulsifiers. Over 12 weeks, their gut barrier failed, microbiome diversity fell, and as inflammation spread through their bodies they ate more and gained weight. Some moved towards type 2 diabetes.
Then there are the impacts of artificial flavouring, says Van Tulleken. When we eat a barbecue-flavoured crisp, for example, our taste receptors are preparing the brain and gut for something meaty, savoury and filling. It never arrives, so we eat more. Likewise, zero calorie sweet-tasting drinks fuel a desire for sugar. “I think this mismatch between what our body is expecting and what it receives is crucial.”
Van Tulleken says he’s now constantly being asked if something is UPF. Baked beans? Jar of pesto? Wine? It’s a minefield. “Sometimes I just have to say, I don’t know.”
Agonising over individual products misses the point, he argues. The better question is, is it real food or — as one scientist described UPF to Van Tulleken — “an industrially produced edible substance.”
He’d like to see UPF treated like cigarettes: limits on marketing, no advertising and UPF risks added to the nutrition guidance. Taxing it is not the answer. “That would exacerbate inequalities. Someone in the lowest 10 per cent of household incomes would end up spending 75-80 per cent of their income on food. I can quit UPF because I have the time to cook and money to buy ingredients. Our potato sourdough loaf from the bakery costs £6. This is not a national solution.”
Reference
Rachel Carlyle - Saturday April 29 2023, 10.30am, The Times