Taking a bioactive whey protein concentrate supplement while dieting has been shown to increase fat loss and retain lean muscle mass.
One hundred fifty-eight obese men and women participated in a study, which was published in Nutrition & Metabolism. All of the subjects were placed on a diet that contained 500 fewer calories per day than their normal diet. Half of the subjects consumed a whey protein supplement daily before breakfast and again before dinner. The remaining subjects consumed a supplement of equal calories. The study period lasted 12 weeks. Body weight and body composition estimates were recorded every four weeks throughout the study period.
Members of both groups lost a significant amount of body weight. Those consuming the whey protein supplement lost slightly more weight, on average, but the difference was not statistically significant. However, members of the whey protein group lost significantly more body fat than the other group (2.81 vs. 1.62 kg) and lost significantly less muscle mass (1.07 vs. 2.41 kg).
The average member of the whey protein supplement group lost 6.1 percent of his or her body fat mass. This result is significant because a 5 percent reduction of body fat mass has been shown to reduce the risk of obesity-related diseases such as diabetes and atherosclerosis, and lean muscle mass boosts metabolism, making losing weight easier and faster.