New research published in Nature Medicine has shown that in a randomized crossover trial, participants eating minimally processed foods lost twice as much weight as those eating more ultra-processed foods, even when both diets were equally nutritionally balanced.
The trial included 55 adults who were split into two groups, 50 of whom completed the study from start to finish. The first group was assigned to eat a diet of minimally processed foods for eight weeks, followed by a four-week washout period of their usual diet, followed by an eight-week diet consisting of mostly ultra-processed foods. The second group was assigned the same diets in the opposite order. The ultra-processed and minimally processed diets were nutritionally matched in terms of macronutrients, and each diet also included the recommended intake of fruits and vegetables. The participants had the foods delivered to their homes and were told to eat as much or as little as they wanted with no restrictions. Their weights were measured throughout the study, and the goal of the study was to see how ultra-processed foods affect body weight and disease risk.
The results showed that the participants lost twice as much weight while eating minimally processed foods compared to ultra-processed foods, even though the two diets were nutritionally matched. Interestingly, while participants lost more weight with the minimally processed diet, they lost some weight with either diet, possibly due to the improved nutritional profile of the study diets compared to their usual diets. The minimally processed diet also led to reductions in fat mass and total body water without impacting muscle or fat-free mass, suggesting that it improved body composition as well as weight.
The authors stated that there are a few practical takeaways from this study. To optimize body composition and reduce disease risk, it is important to focus on minimally processed foods such as fruits, vegetables, and nuts while avoiding processed foods that contain excess salt, saturated fat, and sugar. Additionally, people should aim to align their diets with general nutritional guidelines, which is likely to reduce weight and disease risk compared to the average diet.
Sources: Nature Medicine, Science Daily
