Soy foods are just as good as animal protein sources if you’re trying to lose weight, according to a small study in Obesity Science & Practice of overweight or obese adults (mostly middle-aged women). Previous research has found that higher protein intake, such as from eggs, can help with weight control by increasing satiety, among other possible mechanisms, plus the protein may help prevent loss of muscle mass, as often occurs with weight loss.
For the new study, half the participants added three daily servings of soy foods (60 grams of protein from a soy patty, bar, and powder) to a calorie-restricted diet, while the other half added the equivalent amount of protein from non-soy food sources (lean meat, poultry, fish, egg whites, and nonfat dairy) on top of their regular protein intake.
Over four months, both groups lost “significant and similar amounts” of weight (about 14 pounds, or 7 percent, on average, of initial weight) and had similar changes in body composition. There were no differences between the groups after an eight-month weight-maintenance phase, either (both groups regained more than half the weight).
“These findings may be particularly useful to those looking to increase their intake of protein from high-quality, vegetarian sources as part of a high-protein, reduced-calorie diet,” the paper concluded. The study, led by researchers at the University of Colorado, was supported by DuPont Health and Nutrition, a food ingredients company that supplied the soy protein.
Also see Types of Soy Foods.