In the fevered world of diet and nutrition, the past year has been dominated by heated arguments about the evils (or not) of ultra-processed foods. These have not just been confined to the media but have, unusually, engendered equally fractious debate in academic circles. So what is the “truth” about UPFs? Are they as bad for health as many claim? And how are consumers, armed with this information, meant to navigate the supermarket aisles?
The processing of food, including cooking, fermentation, pickling, curing and smoking, is as ancient as humankind. These processes reduced the chances of food poisoning, increased nutritional availability and ensured that we had a predictable source of calories through seasonal changes in the availability of fresh food. They were critical to our ability as a species to survive and eventually thrive.
But UPFs are a different beast – they are the products of industrial processing methods that we cannot replicate in a domestic situation. They include pretty much all carbonated drinks, ice-cream, biscuits, margarines, pastries, cakes, breakfast cereals, stock cubes, infant formulas and mass-produced packaged breads.
They are also cheap to produce, and because of their long shelf-lives are easy to store and transport. They are inexpensive and more likely to be bought and consumed by those less privileged in society. On average, here in the UK, we get about 50% of our calories from UPFs and the ubiquity with which these foods are available merits sober debate.
But at the same time, it is intriguing, to me at least, that some UPFs have not only avoided being tarred by the same brush, but also seem to be associated with an enlightened way of healthy eating.
The menagerie of plant-based dairy replacements and faux-meat burgers, as well as many other “premium” ultra-processed foods that find their way into higher-end supermarkets and restaurants, are a case in point. In my view, these foods have escaped the kind of scrutiny saved for mainstream UPFs. But from a processing standpoint, there is really no difference between oat milk creme fraiche and your standard dairy ice-cream, or a frozen beef burger patty and a burger made from soy protein.
From a nutritional perspective, oat milk has a lot of oil and emulsifiers and other additives, and a faux-meat burger is still high in sugar, salt and fat; looking through a different lens, one might even consider them junk foods. And yet, the debate around UPFs rarely interrogates why we label some of these foods as more harmful than others.
There is more than ample evidence that consumption of too much ultra-processed food is linked to poorer health outcomes. Most recently a meta analysis of 45 different studies encompassing nearly 10 million people and published in the British Medical Journal reported links with 32 health concerns, spanning early death, cancer, mental health, respiratory, cardiovascular, gastrointestinal and metabolic health outcomes.
This makes sense when you look at how UPFs are made. Most UPFs are inherently lower in protein and fibre and higher in sugar, salt and fat. But the way we currently talk about UPFs strikes me as unhelpful. The term covers such a broad spectrum of different foods, from those that have been almost completely reconstructed from their base constituents, to otherwise minimally processed foods with a few industrial additives, such as a natural yoghurt, with a small amount of UPF jam.
I can absolutely understand how eating too much of the former can lead to poorer health outcomes. The latter, however, includes mass-produced supermarket bread, where a large proportion of consumed UPF calories come from. Sure, you can go to a bougie bakery and purchase an artisanal sourdough without any additives that will cost much more and taste better than a supermarket loaf. But ultimately, bread is made from flour, salt, water and yeast. Taste aside, supermarket bread is no worse for you than fancy bread.
I am an unashamed champion of improving our diets in order to try to stem the current tsunami of diet-related illnesses, and there are certainly many foods that we undoubtedly have to eat a lot less of. To do so, we need to, first and foremost, focus on the nutritional content of our food; we should be looking to consume enough protein and fibre, and a little less sugar, salt and saturated fats. And the reality is that the only way to do this equitably is to make the healthy choice the cheaper, more convenient and easier option.
I fear that the UPF concept is too imprecise to be an arbiter of how healthy or unhealthy a particular food might be, and even worse, that it is currently being used as another cudgel to food-shame others; while at the same time, the privileged in society celebrate and congratulate themselves for eating similarly processed foods that simply have better PR.
Giles Yeo is professor of molecular neuroendocrinology at the Medical Research Council Metabolic Diseases Unit at the University of Cambridge
