may be an ideal source of protein during weight loss due to its nutrient partitioning effects working to enhance fat loss andpreserve lean tissue. A distinguishing feature of whey is the complex protein source with a high prevalen
ce of essential amino acids. Whey also contains a higher proportion of branched chain amino acids (BCAA), especially leucine, which triggers protein synthesis and greater muscle mass. In addition to promoting muscle anabolism and strength, there is evidence that
may also promote body weight and fat loss. Greater weight and fat loss could partially be attributed to increased thermogenesis compared to other protein sources like soy and equal amounts of carbohydrate. A recent clinical study in 90 overweight men and women tracked body weight and composition over a 23 week period during which they supplemented twice per day (56 grams total) with beverages containing whey protein, soy protein, or carbohydrate while following their normal diet. The group supplementing with whey showed the greatest loss in body weight, body fat, and waist circumference. Compared to the carbohydrate group, the whey group lost 4 more pounds body weight and 5 more pounds of fat mass. Since whey is nutrient dense but relatively low in energy (~4 kcal/g), supplementation is an efficient method to promote fat loss while retaining lean mass.
Baer DJ, Stote KS, Paul DR, Harris GK, Rumpler WV, Clevidence BA. Whey Protein but Not Soy Protein Supplementation Alters Body Weight and Composition in Free-Living Overweight and Obese Adults. J Nutr. 2011 Jun 15.