Yogurt has all the benefits of milk, plus active cultures that boost the number of germ-fighting bacteria along your intestinal walls, says Mueller. Why does that matter? It helps keep you from getting sick. Studies show that people who eat yogurt most often are less likely to catch a cold than people who rarely eat the stuff. Like milk, yogurt contains calcium that not only boosts fat-burning but also helps you feel satiated, making it an ideal food for weight loss. "Try to buy yogurt that is less than a week old to ensure you're getting the most benefit from the active cultures," she says. (The later the product's expiration date, the newer it is.) One word of caution: Most yogurt is packed with added sugar and high-fructose corn syrup.