In a study comparing liquid meal replacements in dieters who consumed 1,200 calories per day, soy-based products were more effective for losing weight than cow's milk products (Journal of the American College of Nutrition, 2005, vol. 24, no. 3). "Using soy meal replacements as part of a low-calorie diet can allow people to lose 30 to 50 pounds if they use three meal replacements and at least five servings of fruits or vegetables daily," says James Anderson, MD, author of the study and part of the Metabolic Research Group at the University of Kentucky.

Aside from its role in weight loss, soy has many other health benefits. Regular intake has been shown to lower blood cholesterol levels, protect against heart attack and osteoporosis, and possibly slow the development of diabetes, says Anderson, who recommends 20 grams of soy protein (approximately three servings) per day and suggests soy milk for a good portion of that amount.