Overeat on a low-protein diet and you’ll gain less weight – but just as much extra body fat – as you would on a high-protein one. That’s the finding from a study published in the Jan. 4 issue of JAMA.
Investigators from the Pennington Biomedical Research Center in Baton Rouge, La., fed low-, normal-, and high-protein diets to 25 healthy adult volunteers, and gave them each around 954 extra calories per day. After eight weeks, those eating the low-protein diets gained 6.97 pounds, compared with 13.3 pounds in the normal-protein group and 14.4 pounds in the high-protein group.
But body fat increases among the three groups were similar, while lean body mass in the low-protein group decreased. Lean body mass in the normal- and high-protein groups went up. Neither the high-protein nor the low-protein diet helped maintain body weight if participants were over-eating, as some research has suggested it might.
An editorial that accompanied the study suggested that healthcare providers might need to concentrate on excess body fat, rather than weight or body mass index, in assessing people’s health risks, and that the focus of obesity treatment should be fat reduction rather than weight loss.