A recent clinical study of 90 overweight men and women tracked body weight and composition over a 23-week period. During this time, the subjects supplemented with beverages containing either whey protein, soy protein or carbs alone while following their normal diet.
The beverages were consumed two times per day (around breakfast and dinner), and contained 200 kcal per serving. The whey and soy beverages contained 28g of protein per serving. Subjects were not given instructions to make dietary alterations during the study other than to consume the beverages twice per day.
The whey protein group showed the greatest loss in body weight, body fat and waist circumference. Compared to the carb-only group, the whey group lost 4 pounds of body weight and 5 pounds of fat mass while the soy group lost 2 pounds of body weight and 2.4 pounds of body fat. The differences became apparent especially after the fourth month of supplementation.
This study indicates that whey may be an ideal source of protein to enhance weight and fat loss, and preserve lean tissue.