A group of researchers at the CAS Institute of Genetics and Developmental Biologyhave subjected 5 different strains of mice to a variety of 30 different diets over 3 months, corresponding to 9 years in humans. Over 100,000 measurements were made of the mice’s body weight changes and their body fat was measured using a micro MRI machine. The result of this enormous study was unequivocal – the only thing that made the mice get fat was eating more fat in their diets. Carbohydrates, including up to 30% of calories coming from sugar, had no effect. Combining sugar with fat had no more impact than fat alone. There was no evidence that low protein (down to 5% of the total calories) stimulated greater intake, suggesting there is no protein target. The researchers believe that dietary fat caused weight gain because fat in the diet uniquely stimulated the reward centers in the brain, thus causing greater intake of calories.

CAS news release, July 13, 2018