A new study has found that people in the UK lost twice as much weight by eating meals typically made at home as they did when consuming store-bought ultraprocessed foods, even if those foods met nutritional guidelines. Researchers provided 55 overweight participants with either minimally processed or ultraprocessed meals for eight weeks, followed by a switch to the opposite diet.
The study found that people on the minimally processed diet lost an average of 2% of their baseline weight over eight weeks, while those on the ultraprocessed diet lost only 1%. However, when scaling up this modest weight loss to a year, it would translate to a significant reduction in body fat.
Experts say that men tend to lose weight faster than women due to having more lean muscle mass and testosterone. The researchers also noted that participants who followed a minimally processed diet tended to eat fewer calories per day, losing more weight and some body fat compared to those on the ultraprocessed diet.
The study’s findings support previous research by Dr. Kevin Hall, who found that people in the US gained weight when consuming ultraprocessed foods despite meeting nutritional guidelines. To reap health benefits from ultraprocessed foods, researchers recommend choosing healthier options with lower levels of added sugars, salt, and saturated fats, as well as higher fiber content.
The results also suggest that processing itself may not be as important for heart health if the foods already meet the standard healthy eating guidance. Further research is needed to better understand this phenomenon.
Source: https://edition.cnn.com/2025/08/04/health/weight-loss-ultraprocessed-food-wellness