In a small randomized controlled study, people lost twice as much weight when their diet was limited to minimal processed food compared to when they switched to a diet that included ultracroced versions of foods, but otherwise was tailored.
The test, published in Nature Medicine by researchers from University College London, contributes to a growing number of evidence that influences food processing, in addition to simple nutritional value, our weight and health. Ultracrocessed food has already been stressed for their link to obesity-hungry by weaker observational studies-but researchers have difficulty strengthening the connection with high-quality studies and understanding their impact on health.
The researchers with ultracroced food in the new test were relatively healthy – as ultracrocessed food proceeds. They include things such as multi-crown breakfast cereals, packaged mueslip, flavored yogurt cups, fruit snacks, commercial premade chicken sandwiches, instant noodles and ready-made lasagna. But in the minimally processed tasting diet, participants received meals from a caterer instead of those of a aisle of a supermarket. The diet included oats with fresh fruit, regular yogurt with roasted oats and fruit, handmade fruit and nut bars, freshly made chicken salad and from switch stir-fry and spaghetti bolognese.
Although the level of processing differed between the diets, it was large-scale food content, proteins, carbohydrates, fiber comparable, just like the proportions of fruit, vegetables, dairy products and starchy food. In general, both diets complied with the nutritional guidance of the British government, called the Eatwell Guide (EWG).
Dietary processing
The test had a crossover design, which means that participants were randomly split to start with the ultracrocessed food (UPF) diet or the minimally processed food (MPF) diet. They stayed on their start diet for eight weeks and then took a break and switched to the other diet. For both diets, food was delivered directly to the houses of the participants. Participants ate what they wanted and usually did not seem to cheat by sneaking other food, based on food days and reported therapy compliance.
Fifty participants completed at least one diet, while 43 completed both diets. The participants were mostly women, with an average age of 43, and they all had a Body Mass Index categorized as overweight or obesity. At the start of the test, ultracrocessed food formed on average almost 70 percent of the standard diets of the participants, and they did not comply with the EWG recommendations.
