“Why is there bacterial slime in my ice cream?” is the title of the first chapter in Dr Chris van Tulleken’s new book, Ultra-Processed People: Why Do We All Eat Stuff That Isn’t Food … and Why Can’t We Stop? It’s an excellent proxy for much of what follows — an unafraid, curious, witty investigation into the inexorable rise and now global dominance of ultra-processed food (commonly referred to as UPF — “junk food” by a newer name) and their effects on our weight, brains, health, traditional food cultures and the environment.

In the book, which has topped bestseller lists in the UK, Van Tulleken unpacks the history, economics and, frankly, deeply frightening nature of the food science underpinning ultra-processed food and the companies that make them, as well as the rapidly growing scientific literature on the many and varied ways they cause us to overeat, gain weight and further damage our health.

How, Van Tulleken asks (and answers), has humanity got to a point where most of what we eat is paste and slime reconstituted in many different forms (Pringles or supermarket ice cream, anyone?), with UPF making up 57% of what the average American and Brit eat every day? 

The figures for South Africa and many other low- or middle-income countries are not yet known — nor does Van Tulleken focus much on the scores of low- and middle-income countries that are prime target markets for multinational food companies exploiting those underregulated markets, apart from Brazil and Ghana. However, a recent dietary intake sample of about 2,500 low-income adults living in Langa, Khayelitsha and Mount Frere by South African researchers showed around 40% UPF consumption.

Read more in Daily Maverick: Studies flagging raised risk of heart attack from ultra-processed foods prompts warning of ‘tidal wave of ill health’

The term ‘ultra-processed’ comes from a processing classification system (called Nova) created in 2010 by a team of Brazilian scientists who categorised foods into four groups, in ascending order of procession, ending with the fourth category of “ultra-processed”. 

All the Group 4 foods consist of formulations of low-cost ingredients that are “mostly of exclusive industrial use, made by a series of industrial processes”, produced mainly to feed the profit motives of the transnational corporations that manufacture them (an axe that Van Tulleken, justifiably, keeps grinding). 

UPF includes many of the items you’d expect: factory-made biscuits, ice cream, chocolates, sweets, crisps, breakfast cereals, prepared frozen foods, salty and sugary snacks, instant noodles, “ready” meals, “fast foods” and, of course, any kind of sweetened drink. 

But it also includes things we’re conditioned to think are “good” for us: low-fat flavoured yogurts, pre-sliced bread (even wholegrain), most granolas, protein and energy bars, store-bought soups, salad dressings and many “plant-based”, gluten-free and vegan foods often featuring elaborate health claims.

The book is partly based on Van Tulleken’s experiment on himself, initially for a six-part podcast documentary he made with his identical twin brother. Van Tulleken embarked on a scientifically controlled diet, first going completely UPF-free for a month, and then on a diet of at least 80% UPF for a month. Throughout both, he was monitored, weighed, measured and tested by scientists at University College London Hospital. 

‘Totally deranged hormones’

At the end of the UPF month, Van Tulleken had gained 6kg, his appetite hormones were “totally deranged” (“the hormone that signals fullness barely responded to a large meal, while the hunger hormone was sky high just moments after eating”), and levels of an inflammation marker (C-reactive protein) had doubled. But the most terrifying result, he said, was an MRI scan, which showed that the connectivity between several regions of his brain had increased, “especially the areas involved in the hormonal control of food intake, and the areas involved in desire and reward”. 

One theory spoken to by his scientific colleagues is that because UPF ends up looking, smelling, and tasting delicious, it leads our brains to expect real nutrition. But because most of the food’s original structure, nutrients, fibre and flavours have been stripped out, and then mimicked by flavour enhancers, emulsifiers, colourants, thickeners and stabilisers, real nutrition never comes. This “mismatch” tricks our brain’s reward systems, making us crave more, and eat more, and still not be satisfied. This, Van Tulleken says — citing reams of new research — is what makes UPF addictive, and partly why it is driving rapidly rising rates of obesity around the world.

“No one is addicted to real food,” he says. Ultra-processed “foods” — or “industrially produced edible substances”, in the words of Fernanda Rauber, one of the Brazilian scientists who defined the term “ultra-processed” — have been processed to the point where they’ve lost most of their nutrients except the calories. 

Read more in Daily Maverick: SAMRC showcases SA poor’s dependency on ultra-processed meals as food basket costs continue to rise

As Van Tulleken himself points out, food processing is not a new phenomenon. Humans have been drying, preserving, fermenting and pickling foods (and drinks) for millennia, partly in a quest to make fresh foods last longer. What is new, since saccharin was accidentally invented from coal tar by a chemist named Constantin Fahlberg in 1879 (he was trying to produce medical compounds), is our modern era of synthetic food chemistry, in which thousands of new artificial ingredients have been developed to serve multinational food corporations’ profit-seeking need to create cheap, tasty foods with mass appeal, long shelf life, and massive profit margins.

More chemically or process-manipulated foods entered diets from the late 18th century, Van Tulleken writes, with their takeover gaining speed from the 1950s onwards, to the point where today UPF forms “a significant part of the diet of nearly every society on Earth”, and in some cases like the UK, the majority part.

So why is this a bad thing, again?

To be clear, UPF in its many forms was a boon for time-poor, cost-conscious consumers. Though Van Tulleken doesn’t exactly let big food off the hook, he does point out that corporations were not (at least, not initially) maliciously manipulating foods to deprive people of nutrition and endanger their health. The TV dinner of the 1950s was a godsend for millions of households. 

But now we know more: Van Tulleken builds the case that it is the additives, stabilisers, emulsifiers, modified starches and the hundreds of industrial manipulations to which these foods are subjected that cause serious, long-term damage to our health. 

And he is upset not only about the costs to human health from a diet heavy in UPF, catastrophic though they are. The “externalised” costs of UPF include environmental destruction (climate change and land use — the industrial food system contributes about 30% of total greenhouse-gas emissions), as well as adding to antibiotic resistance (antibiotics are widely used in factory-farmed animals) and plastic pollution (Coca-Cola, PepsiCo and Nestlé were named the world’s top three plastic polluters in a global audit in 2020) — and those are just the three “most significant” costs, Van Tulleken says.

He describes a “new, parallel ecosystem” with its own “arms races”. Its goal? To extract our money. The bait? UPF, which today has “evolved to subvert the systems in the body that regulate weight and many other functions”. 

Van Tulleken’s discussion of UPF is pioneering not least because, he says, UPF is not just the food: “Ultra-processing also includes other, more indirect processes — deceptive marketing, bogus court cases, secret lobbying, fraudulent research — all of which are vital for corporations to extract that money”. 

Formerly an HIV lab scientist, Van Tulleken can sometimes go too far down explanatory rabbit holes, but he avoids lecturing or moralising about individual responsibility or choice. “What we eat is determined by the food around us, its price and how it’s marketed — this is what needs to change.”

He places the blame for humanity’s overeating, obesity and related health crises squarely at the feet of big food monoliths. “If you struggle with eating,” he tweeted on the day of the book’s release, “remember, it’s not you, it’s the food.”

Van Tulleken also suggests that anyone wishing to give up UPF continue eating it while reading the book (à la Alan Carr’s Easy Way to Stop Smoking), the idea being that soon, your UPF sensors will be on red alert and it will become disgusting to you. 

And he may be right. Read about the horrors of various “gums” (example: the slime that bacteria produce to allow them to cling to surfaces, also known as xanthan gum — see that first chapter title), the thousands of other processes and chemicals that disrupt our bodies’ and brains’ natural ability to regulate what and how much we eat, and you may well decide to start reading ingredients on labels and swear off UPF forever.

You be the judge. It is hard to do justice here to Van Tulleken’s very persuasive case — the delight is in the detail, and in his inquiring mind that delves into history, economics, and food science — and several fascinating experts he talks to who are working in this field. 

And I’d second the advice of food writer Bee Wilson (a legend in her own right), whose blurb for the book said just: “If you only read one diet or nutrition book in your life, make it this one.” DM

Ultra-Processed People: Why Do We All Eat Stuff That Isn’t Food … and Why Can’t We Stop?, by Dr Chris van Tulleken, published by Cornerstone Press, is available in South Africa at good bookshops and online.