YOGURT: Yogurt has probiotics beneficial bugs that live in your digestive tract and help crowd out harmful microorganisms that can cause intestinal infections. With the right ratio of protein to carbohydrates, yogurt makes an excellent post-sweat-session snack. One serving is a significant source of potassium, phosphorous, riboflavin, iodine, zinc, and vitamin B5 (pantothenic acid). Yogurt also contains B12, which maintains red blood cells and helps keep your nervous system functioning properly. Eat 18 ounces a day and you can drop a jeans size. People who ate that much — in conjunction with cutting their total calories — lost 22 percent more weight and 81 percent more belly fat than dieters who skipped the snack, according to research from the University of Tennessee, Knoxville. They also retained one-third more calorie-torching lean muscle mass, which can help you maintain weight loss.