Chris van Tulleken refuses to tell me what to have for breakfast. “Everyone thinks that I have a strong opinion about what they should eat,” he tells me, as I hesitate between the eggs benedict and the full English. “And I have almost no opinion.”
Now, this isn’t quite true. When I tell him later that I’ve decided that the occasional full-sugar cola is probably better than multiple diet sodas every day, he replies: “Enjoy the phosphoric acid leaching the minerals out of your bones.” Which sounds a little judgmental, if I’m honest. (Soft drinks have been linked to bone fractures, but their manufacturers dispute that there is a causal relationship.) There’s a very good reason that van Tulleken refuses to dictate my breakfast order: He has just published a book identifying ultra-processed food, or UPF, as a great evil in our diets, and has therefore signed up for a lifetime of being portrayed as a joyless, middle-class puritan who wants us to live on mung beans and kombucha. As part of the research for Ultra-processed People, he ate a UPF-heavy diet for a month—a stunt reminiscent of Morgan Spurlock’s Super Size Me, and one open to the same criticism about replacing science with showmanship. “By the fourth week, it had started to have very noticeable physical effects, forcing me to loosen my belt by two notches,” he writes. “In just a few weeks, I felt like I’d aged ten years. I was aching, exhausted, miserable and angry.”
Public-health campaigns against “junk food”—a shorthand for foods with high fat, sugar, and salt content—are well established and formed one of Michelle Obama’s priorities as first lady. Van Tulleken’s case against UPF is different. The problem isn’t the food’s nutritional profile, per se, but the industrial processes to which it has been subjected, and the artificial chemicals used to improve its flavor and shelf life. He argues that we should be more wary of a diet soda than a cookie baked from scratch at home, because UPF is stuffed full of chemicals that disrupt our body’s ability to regulate appetite and digestion. He cites a 2019 research study, led by Kevin D. Hall, which gave participants either an ultra-processed or unprocessed diet and found that the former group ate more calories. Rather than “food,” van Tulleken thinks UPF is better described as an “addictive edible substance.” If that’s true, it’s bad news for most Americans: UPF makes up 57 percent of the U.S. diet.
Van Tulleken is an infectious-diseases doctor. He is also a twin, and until last year his brother Xand was more than 30 pounds heavier than he was (the pair had the biggest weight discrepancy in the King’s College twin study). Then the brothers made a podcast about ultra-processed food, which Chris already believed was bad, but to which Xand was still addicted. Chris discovered during that process that Xand’s other problem was him. “For Xand to set about losing weight on his own would have been to lose a decade-long argument with me,” Chris told me when I interviewed the twins two years ago.
So he won’t tell me what to have for breakfast. But he will tell me that the English muffin in front of me—pillowy soft, when it arrives, and pure white—looks ultra-processed. UPF is typically defined as anything with one or more ingredients that you wouldn’t tend to find in a home kitchen: stabilizers, modified starches, industrial sweeteners, glycerine, xanthan gum. (A more comprehensive classification system, the NOVA scale, has been developed by Brazilian researchers.) These industrial additives keep food fresh for longer, making supply chains work, and tend to be cheaper than the natural ingredients they replace. They allow food companies to make a profit, and consumers to spend less of their disposable income on food: In the U.S., that figure was 10.3 percent in 2021, down from 16 percent in the 1960s. Ultra-processed People begins with a scene in which van Tulleken gives his 3-year-old daughter, Lyra, a tub of ice cream in a park. When she runs off to play, he realizes that the snack isn’t melting into liquid; it has instead become “tepid gelatinous foam.” The culprit is xanthan gum, a substance made from the slime that bacteria excrete to cling to surfaces.
Before reading van Tulleken’s work, I felt pretty confident that junk food was bad. That didn’t stop me from eating it, however. Learning about UPF is a different experience—you begin to realize that some of this stuff is barely food at all. I had a revelation at a railway-station snack shop the day before meeting van Tulleken, when I looked at shelves of candy bars that filled my entire field of vision. Suddenly, I thought: Hang on, this chocolate can survive at room temperature. For a year. He told me he had previously experienced a similar moment of unease, which led him to think: “How would a normal human try and figure out what they should eat in this station?”
Van Tulleken argues that the food industry has been engaged in a long-term campaign to sell us more of its products, with well-funded laboratories taking branded snacks and ready meals and fine-tuning them like a Formula 1 engine. It’s not a coincidence that you open a packet of Pringles and find out that, in the words of the brand’s former slogan, “once you pop you can’t stop.” Each chip has been engineered into an identical saddle shape the size of a child’s fist. (On the podcast, Chris made Xand add water to the crisps and eat spoonfuls of the resulting slop, which forced his twin to confront the real product underneath the magic.) Even when it appears to be low-calorie, UPF drives overeating, he argues, because it interacts with our body in a different way than, say, a whole apple does. The recommended serving size of Pringles is 13 chips. Yeah, right.
At some point, my eggs benedict arrive, and I start eating—noting that, as someone with braces, I’m quite grateful that most bread is gummably squishy. “The reason you need braces is, of course, the same reason I did,” van Tulleken says. “Our jaws and our facial bones didn’t develop, because we just ate mushy food.” Wait, I say—the incels were right about “mewing”? (A brief pause as I explain the popular internet practice of building jaw strength to appear more masculine.) Van Tulleken looks concerned, as if I am already mentally bracketing him with sweaty, alarming people who make YouTube videos about GigaChads. “I’m not a clean-eating freak,” he says. “And I don’t want to give everyone a neurosis. It’s not all about the additives; I don’t want to ban stuff. I think that transnational food corporations are predatory, but they’re not evil by design. They’re just hemmed in by late capitalism.”
Because of his work as a doctor, van Tulleken has a horror of becoming known as a “posh white guy” handing out diet advice to people who can afford to drop $8 on a sourdough loaf. One of his clinics is for migrants, many of whom live in hostels, and, he says, “they’re all constipated; it’s quite often one of the main problems that they have.” He advised one man to eat an apple whenever he could, for the fiber, and was reminded that the British government gives asylum seekers in full-board accommodation only £8 ($10) a week for any extra food or other essential items. Further up the income scale, many people still struggle to find nearby shops that sell fresh fruit and vegetables. Van Tulleken says that whereas Britain has food swamps—“There is real food in the swamp; you just have to wade through it and get it,” he tells me—some parts of America have true food deserts, where the only thing available is UPF.
Van Tulleken won’t be drawn on his own political beliefs. But he is aware that he needs to speak the language of the right to make his case, because the libertarian emphasis on personal responsibility has ended up providing cover for the food industry. “What I would like is people to have freedom of choice,” he says. “At the moment, we have a nanny state governed by unelected corporations the size of Venezuela”—the handful of confectionary giants responsible for the candy bars filling the shop on the railway platform I visited. “Why can’t you buy a banana on that platform?” he asks. And there’s another reason not to lay down commands about good and bad foods: “People hate it.” He hopes that reading his book is a little like the experience of mainlining cigarettes through Allen Carr’s The Easy Way to Stop Smoking. By the end, you’ve disgusted yourself. You want to quit.
His nemesis on that front is Christopher Snowdon, the head of lifestyle economics at the Institute for Economic Affairs, a London-based free-market think tank, who has had great fun mocking van Tulleken’s experiment—in which he ate UPF for a month, and then cut it out completely for the next. How addictive can UPF be if you can give it up like that? Snowdon asks, calling UPF “the latest bogeyman in diet quackery.” He argues that “the answer is obviously to not consume too many calories regardless of what kind of food you eat.”
Some nutrition experts also caution against demonizing UPF. “I think it’s unlikely it’s addictive,” Clare Thornton-Wood, a registered dietitian and spokesperson for the British Dietetic Association, told me. “But the behaviors might be addictive—if a family always has chicken nuggets for dinner, children are conditioned to eat the food they grow up with.” In an ideal world, we would all eat less UPF, but “in the world we live in, it will form part of your diet.” She had packed a cereal bar in her bag that morning, she told me, knowing that she would be out all day.
Come on, then, I say to van Tulleken. How are you going to deal with the accusation that you’re a smug do-gooder trying to crush people’s enjoyment of their breakfast? “You have to not care,” he says. “Second, I’m not calling for a ban. I don’t accept [that] this food brings joy, but that’s up to you.” He has personally gone cold (unprocessed, presumably free-range) turkey on UPF, as has Xand. Their mother is delighted, as the kind of person who makes her own baked beans from scratch. He notes the bemused face I make at the idea of anyone doing this.
However, he does have some practical proposals. First, that every doctor should be obliged to declare outside income from food companies to their professional regulator—and the same norm should be enforced on academics writing research papers on nutrition. Second, the traffic-light labeling system that some countries use to identify junk food could be revised to make UPF more obvious to consumers. Marketing UPF to children could be restricted, as it is in Chile. No more cute cartoon characters on cereal boxes and adverts on teatime television. In the United States, such efforts would likely have to be either voluntary, enacted at the state level, or enforced by platforms such as YouTube Kids or Disney. (The Federal Trade Commission proposed nationwide voluntary restrictions on advertising junk food to children under 17 in 2011 but weakened these following industry pressure.)
Finally, those who can cook food from scratch, and spend more of their disposable income on high-quality ingredients, should do so. I tell him this last one sounds about as appealing as the antidotes to climate change that involve … well, flying less, quitting fast fashion, and having a colder home. He reluctantly agrees, noting that he is also braced to be called a misogynist by critics claiming that “I hate women because I want to make food less convenient.”
The example that gives him hope is the tobacco industry. After the links between smoking and lung cancer were discovered and publicized, health authorities in the U.S. and Europe curtailed tobacco sponsorship of sports events, instituted warnings on cigarette packs, and took a harder line on sales to minors. But that also came with a cultural shift, as more public spaces became “smoke free,” making tobacco easier to avoid. Twenty years ago, the restaurant in which van Tulleken and I ate our eggs benedict would have been full of other people’s smoke.
Looking back, I say, I don’t know why I put up with being forced into an unhealthy environment. Perhaps one day that’s how we will feel about convenience stores and supermarkets filled with food that isn’t really food.