Book Report: Ultra Processed People

I went into reading Ultra Processed People with an open mind. I’d heard from colleagues and friends that author Chris van Tulleken had done a pretty good job of de-centring a personal responsibility narrative. His emphasis was on encouraging people to think about the influence of the food industry in shaping our eating habits; the so-called ‘commercial determinants of health’. The thesis of the book is that commercial interests have paved the way for a food system that is overly reliant on concoctions of synthetic chemicals like flavourings, colourings and emulsifiers that are reconstituted into cheap ‘food-like substances’ rather than ‘real’ food. These fake foods and the chemicals contained therein are hazardous to our health.

To frame his argument, van Tulleken uses the NOVA classification, which ranks foods into four discrete categories: unprocessed or minimally processed foods like milk; processed culinary ingredients like salt and honey; processed foods like cheese or sourdough bread; and finally ultra processed foods (UPF) like supermarket bread and breakfast cereals. UPF, van Tulleken posits, harms our bodies directly, by ‘increasing rates of cancer, metabolic disease and mental illness’. But it also causes human suffering through ‘displacing food cultures, and driving inequality, poverty and early death’, as well as through environmental damage. He vignettes his breakdown of the science with personal anecdotes of ‘experimenting’ on his own body; first with a UPF-free diet, followed by a diet high in UPF. 

And certainly, his narrative is compelling. He is a good storyteller. He writes with conviction. At several points I had to consult with the Nutrition Group Chat, and various smart friends received a text amounting to ‘am I losing my mind or…?’. This confident storytelling is probably why Ultra Processed People (UPP) has been such a runaway success; A Sunday Times bestseller; winner of the Fortnum and Mason’s Debut Food Book of the Year in 2024; translated into (as far as I could tell) Romanian, Dutch, German, Norwegian, Portuguese, Czech, Swedish, Italian, Spanish, Slovakian, Bulgarian, Finnish, Turkish, and French. It has also enjoyed a hardback and paperback release in the UK, Canada, and the US. The UK edition alone has sold almost 320,000 copies according to Nielsen Bookscan (December 2024) and that is excluding audio and e-book sales. That represents almost £3.5 million in sales, just for the UK release of the physical book. 

And while the assuredness in the writing and storytelling makes for a convincing read, it is also the book’s undoing. Over and over again, van Tulleken writes in absolutes, using causative language and leaving little space for doubt and uncertainty. This belies the ambiguity and unknowns that undergird our understanding of the research around UPF. We should be wary – and in fact reading UPP made me weary – of binaries. ‘Certainty is a dead space’ writes author Katherine May in Wintering: The Power of Rest and Retreat in Difficult Times, ‘in which there’s no more room to grow’. Compelling writing is not the same thing as good writing. Just as compelling science isn’t automatically synonymous with good science. 

May continues that ‘wavering is painful’. Indeed. Van Tulleken seems deeply reluctant to sit in the discomfort of not knowing. And while there may be a broad consensus that UPF is a signal in the noise of contributors to ill-health, as of yet, we don’t know exactly how loud the signal is, nor can we fully decipher it. 

Certainty bulldozes complexity. Research published in May 2024 by Harvard University highlights some of the contradictions. They found that eating sugar sweetened breakfast cereal, processed meat, and sugar or artificially sweetened drinks carried a risk of premature death. Foods like unsweetened breakfast cereals and wholegrain bread, although considered UPF, did not carry the same increased risk. What's more, the overall increased risk (or effect size) was small. The researchers concluded what any nutritionist or dietitian would tell you: overall diet quality is what matters the most. Van Tulleken speaks with such assured authority so as to leave no space for caveat or nuance. 

With the research that van Tulleken cites in the book, he is selective in how he reports the data, glossing over the parts that don’t fit neatly with his definitive narrative. For instance, in the section where he describes the work of researcher Kevin Hall, I have written in the margin ‘a deliberate misrepresentation of this study’. I’ve written in-depth about how Hall’s work is frequently weaponised to drive a specific narrative. But the study itself is full of tensions, discrepancies, and unanswered questions. In some cases it makes the opposite case that UPF critics often cite. For instance, the researchers didn’t find evidence that UPF is hyperpalatable or that there was elevated blood glucose levels in the groups eating more UPF. It also found weight gain began to stabilise relatively quickly after beginning the UPF diet. This raises something troubling: either van Tulleken wasn’t reading the study very carefully, or, I was right about the deliberate misleading. Either way isn’t great. I'm also troubled by how van Tulleken is comfortable citing animal and in vitro research when it furthers his argument; criticising the same methodology when it refutes it.