When it comes to packing on the pounds, it turns out that not all excess weight gain is the same. At least those are the results of a new study from the Pennington Biomedical Research Center in Baton Rouge, which found that, when it comes to consuming excess calories, diets low in protein actually lead to loss of lean body mass (muscle and organ tissue), unlike normal or high-protein diets, which increase lean body mass.
In the study, published in the Journal of the American Medical Association, researchers recruited 25 adults to live in an in-patient setting for eight weeks, during which time they were fed nearly 1,000 extra calories per day. Participants received those calories as either a low-protein diet (1.6 ounces daily), a normal-protein diet (5 ounces daily), or a high-protein diet (8 ounces daily). While all three groups gained about 8 pounds of body fat, lean body mass decreased by 1.5 pounds in the low-protein group, but increased by 6 and 7 pounds in the normal- and high-protein groups, respectively.
Though all participants gained weight, lead author Dr. George Bray points out, The bathroom scale doesn t tell you what the composition of your body is. In this study, it s clear that low-protein diets may adversely affect lean body mass.
When you re talking about diets and how to lose or gain weight, says ACSH's Dr. Ruth Kava, the composition of the diet is very important. People don t want to lose muscle mass since, compared to fat, muscle metabolizes more calories and is important for leading an active lifestyle.