In a study conducted among 25 healthy individuals living in a controlled setting who were randomized to overconsumption of different levels of protein diets, those consuming the low-protein diet had less weight gain compared to those consuming normal and high protein diets, and calories alone, and not protein appeared to contribute to an increase in body fat, according to a study in the January 4 issue of JAMA. The researchers also found that protein did contribute to changes in energy expenditure and lean body mass.