Scientific research consistently shows that people who eat large quantities of Ultra Processed Foods are obese or overweight. Yet the reasons why this correlation exists isn't exactly clear....
A recent study from University College London, published in Nature Medicine, adds further insight. 55 adults were asked to stick to two different diets: one comprising predominantly UPFs and the other just regular foods. The two diets were specifically matched for fat, sugar, protein, and carbohydrate content. Meals were also designed to be similar in type — homemade lasagne to a supermarket ready meal.
The outcomes were informative. On the UPF regimen, participants lost 1% of their body weight, but on the MPF regimen they lost 2%. That sounds inconsequential, but in a year it means losing about 13% of body weight for men and about 9% for women. Most tellingly, perhaps, was that participants on the UPF regimen experienced more cravings, which led them to consume more calories overall.
Cravings, Speed, and Satiety
The study finds that sugar and fat content are not the only factors that make UPFs fattening, it's also a matter of how we process food. Ultra-processing has been known to alter food metabolism and satiety. A 2019 U.S. National Institutes of Health (NIH) trial found the same: participants given UPFs consumed approximately 500 more calories daily compared to eating minimally processed foods, although the two diets were nutritionally equivalent (NIH, 2019).
Why does this happen?
For starters UPFs tend to be softer so they require less chewing which gives the brain less time to register fullness and so the desire to eat more.
And additives such as emulsifiers and flavour enhancers may also furhter stimulate appetite.
It's also possible that UPFs are not just calorically dense but have negative impacts on metabolic health aas well.
Final thoughts
If UPFs are bad for our health we should be worried... more than half of the typical diet in the UK alone now comes from UPFs.
The simple facts show us that even if calories and nutrients are the same, eating real food has better weight outcomes and possibly lesser long-term health impacts.
