After 23 weeks, the whey group had lost an average of 3.9 pounds more body weight and 5 pounds more fat-mass compared to placebo. The soy group lost about half these amounts compared to placebo, which doctors said was not statistically significant.
The whey group also lost one inch around the waist while the soy and placebo groups had not changed. Researchers also measured ghrelin, a hormone the body produces to tell the brain when it is time to eat, and found lower levels of ghrelin in the whey group compared to soy and placebo.