Leading researchers from the University of Bristol conducted a re-analysis of the results of an experiment organized by the National Institutes of Health in the USA. During the study, participants consumed only natural foods for two weeks, and then switched to a diet of ultra-processed foods for the same period. It is important to note that the composition of nutrients—fats, sugars, salt, and fiber—remained unchanged.
The main conclusion of the study showed that on a diet of unprocessed foods, participants consumed significantly more by weight, yet their calorie intake decreased by 300 kcal per day. This is explained by the fact that natural food, rich in vegetables and fruits, has low energy density. The high water and fiber content contributed to quick satiety without overloading the body with excess calories.
On the other hand, when consuming ultra-processed foods, the situation was the opposite. Even small portions contained high calorie content. Industrial food often combines carbohydrates and fats in such proportions that significantly activate the pleasure centers in the brain, which can lead to overeating. Additionally, the addition of vitamins to high-calorie products deprives the body of the need to seek micronutrients from healthier, low-calorie sources like vegetables.
Professor Jeff Brunstrom, one of the authors of the study, emphasized that people intuitively make the right choices when offered natural foods. “Food choices are not random—we seem to make more conscious choices than previously thought when foods are presented in their natural form,” he noted. This underscores that the quality of food is crucial for healthy eating, allowing the body to find a balance between satiety, pleasure, and benefit.
