Good news for all of you body builders and dieters out there. Research recently conducted at the Pennington Biomedical Research Center in Baton Rouge, La has suggested that diets focusing on high protein foods are no more likely to increase body fat than diets low in protein. Researchers went on to conclude that “calories alone, however, contributed to the increase in body fat.”(JAMA: The Journal of the American Medical Association, 2012; 307 (1): 47 DOI: 10.1001/jama.2011.1918)
The main objective of the study was to “To evaluate the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition.” The scientists studied 25 healthy men and women volunteers between the ages of 18 and 35. The study started with the first volunteer in June of 2005 and concluded with the last volunteer in October 2007. All study participants were kept in an inpatient metabolic unit for 10 – 12 weeks.
For the first 13 to 25 days, these volunteers were fed a weight-stabilizing diet – in other words, their weight stayed the same. For the remaining 8 weeks, volunteers were overfed one of 3 different diets – low protein (5%), normal protein (15%) or high protein (25%), with the intention of weight gain.
All of the study volunteers, both men and women, gained weight on the 8 week, overfeeding plan. However, all 3 groups gained similar amounts of body fat. The study authors summarized their findings with this statement, “In summary, weight gain when eating a low protein diet (5 percent of energy from protein) was blunted compared with weight gain when eating a normal protein diet (15 percent of energy from protein) with the same number of extra calories. Calories alone, however, contributed to the increase in body fat. In contrast, protein contributed to the changes in energy expenditure and lean body mass, but not to the increase in body fat.”