While eating foods with low — versus moderate or high — protein may result in less weight gain, excess calories increase body fat indiscriminately, suggests a pioneering, small study of young adults recently published in the Journal of the American Medical Association.
The study of 25 young adults, which is one of the first systematic, randomized clinical trials to assess deliberate overeating, suggests gains in overall body fat are unrelated to the protein levels within foods.
In summarizing the study’s primary findings its lead author told a JAMA interviewer (and we quote): ‘diet composition may deceive you if you only look at the scale, since the people eating the low-protein diet gained less weight but not less fat. The scale can’t tell fat from nonfat weight’ (end of quote).
The study also found higher to moderate protein diets comparatively increase lean body mass. The study’s primary findings were seen to suggest important dietary implications for patients and health care providers in an accompanying editorial.
The study, conducted by the Pennington Biomedical Research Center in Baton Rouge, LA, asked 25 healthy young men and women to stay at a medical center for 13-25 days and deliberately eat a diet with 40 percent more calories than the participants needed to maintain their weight. All participants received the same calories but randomized groups ate a low, moderate, or high protein diet respectively.
High protein foods include: cheese, lean meats, fish, lentils and peanuts. Low protein foods include: bread, potato chips, and ice cream.
The study’s efforts to assess eating habits by asking otherwise healthy participants (ages 18-35) to live and eat at an inpatient center [as well as deliberatelyovereat via planned meals] may explain why controlled, systematic, randomized, and ethical clinical trials of overeating are difficult to arrange.
Although the research’s low number of participants means its findings are not generalizeable to a larger population of young persons, the study’s controlled conditions and insights seem unique.
The editorial that accompanies the study notes its implications for patients include:
The editorial’s authors add the finding (that fat was gained similarly by all three groups regardless of protein levels) is important because excess fat [as well as one’s body mass index] are associated with obesity-related medical conditions. To determine your body mass index, see ‘Calculate your body mass index,’ which is available in the ‘health check tools’ section of MedlinePlus.gov’s weight control health topic page.
The editorial’s authors add the study’s implications for physicians are (and we quote): ‘Clinicians should consider assessing a patient’s overall fatness rather than simply measuring body weight or body mass index and concentrate on the potential complications of excess fat accumulation. The goals for obesity treatment should involve fat reduction rather than simply weight loss, along with a better understanding of nutrition science’ (end of quote).