Humanism
What will people do?
21 August 2025
A Revolutionary Study by London Scientists
Two British research units, University College Hospital and University College London Hospitals, conducted an experiment to test whether processed food slows down weight loss. 55 people were involved in the analysis and divided into two groups. Both groups were given nutritionally balanced meals, but in excess. There was so much food that it exceeded the subjects’ daily caloric needs. However, they were given free rein – they could eat as much or as little as they wanted. The most important aspect of the study was the use of ultra-processed (UPF) and minimally processed foods (MPF).
The first group’s diet was based on minimally processed food for eight weeks. This was followed by a four-week “cleansing” period, during which the subjects returned to their own daily diets. Then, the same group was fed ultra-processed food for another eight weeks. The procedure for the second group was the same, but in the reverse order. For the first eight weeks, their plates contained UPF meals, and after a four-week break, they switched to a minimally processed diet for eight weeks.
This was the first study of its kind in the world. When composing meals for both groups, the researchers adhered to the Eatwell Guide, which outlines the UK government’s recommendations for healthy eating. Both groups had the same calculated caloric value of their meals. The only difference was the degree of food processing.
Recommended reading: Why Your Healthy Diet Isn’t Working: The Hidden Role of Meal Timing
The Research is Clear. Processed Food Slows Down Weight Loss
The people who consumed a minimally processed diet lost more weight than those on an ultra-processed diet. The results of the experiment were described in the scientific journal Nature Medicine.
“In conclusion, eight-week non-rigorous MPF and UPF diets, consumed to satiety and meeting UK dietary guidelines, resulted in weight loss, with significantly greater weight reductions observed with the MPF diet than with the UPF diet. These findings underscore the importance of the degree of food processing in public health policy and dietary guidelines and the need to supplement existing recommendations,” the study reads.
As the analysis showed, people on the minimally processed diet experienced a calorie deficit of 290 calories. Volunteers who consumed ultra-processed food ended up eating only about 120 calories less than their bodies needed. It was these differences that contributed to the subjects losing more weight when they ate minimally processed food.
In the case of MPF, there was a 2.06% body weight reduction, while the UPF diet resulted in a 1.05% reduction. This is almost half the result of the group that ate minimally processed food. The people on the minimally processed diet reduced their body fat levels and accumulated water. However, there were no changes in muscle mass, which indicates the maintenance of a better body composition.
The conclusion from this research is simple: ultra-processed food slows down weight loss. The researchers who conducted the analysis suggest that even if we follow dietary recommendations, the degree of meal processing can contribute to more – or less – effective weight reduction.
Read the original article: Ograniczasz posiłki i nie chudniesz? Kalorie to nie wszystko
