Pick up some soy. You can quite literally "sprinkle" this inexpensive, nutrient-heavy ingredient on your food for small boosts in your health. "Soy is a complete protein, and studies have shown that a combo of soy, whey, and casein is optimal to promote muscle growth," says Dr. Clark. While more research has to be done, studies over the years have suggested that consuming soy can lower bad cholesterol and possibly prevent cancer. Clark suggests buying soy granules, with 22 grams of soy protein per quarter cup. "Mix with cereal, yogurt or sprinkle on salads or pasta sauce," she says, adding that it definitely won't hurt your wallet: "A 30 day supply costs $5.50."