Yes, people can lose weight and stay healthy while eating “ultra-processed food”
Are ultra-processed foods making us fat? Proponents of this faddish theory may not welcome the results of a new randomised controlled trial published in Nature this week, which showed that people can lose weight on a diet of “UPFs”.
The study split participants into two groups. One group was given 4,000 calories of ultra-processed food (UPF) a day. The other was given 4,000 calories of “minimally processed” food. Both groups were told they could eat as much as they liked and, crucially, both diets were in line with the UK government’s Eatwell Guide, which is to say that they were nutritionally sound.
After two weeks, both groups had lost weight. The people on the minimally processed diet lost more weight than the people on the UPF diet but whatever magical properties of factory production supposedly make UPF inherently unhealthy failed to strike when the food was nutritionally balanced.
Moreover, the people on the UPF diet reported that the food was tastier, easier to prepare and more convenient than the minimally processed food. That the UPF diet was easier to adhere to is evident from the fact that several people on the minimally processed diet dropped out of the study whereas everyone on the minimally processed diet stayed until the end. Having food that tastes good and that people want to eat may not be a consideration for the high priests of “public health’” but it matters to the rest of us. This study shows that food can be healthy, nutritious and aid weight loss regardless of how it is made.
The researchers who conducted the experiment — who included Chris van Tulleken, author of Ultra-Processed People — were surprised and perhaps a little disappointed that the people who consumed the UPF diet lost weight. They say their findings were “in contrast with our hypothesis given the body of observational evidence linking UPF with weight gain”, but observational epidemiology is notoriously useless when studying nutrition. If you want to study what people eat, you have to monitor them carefully and control their diets.
The media have, not unpredictably, focused on the added weight loss benefits of the minimally processed diet. The Financial Times even ran with the headline: “Ultra-processed food slows weight loss even on healthy diet, study finds”. This is burying the lede. The lesson from this study is that a calorie is a calorie. Sure, people will tend to eat more if the food tastes good, but there is nothing special about food wrapped in plastic, made in factories or sold in supermarkets. There never was.
