Beef, chicken, pork, fish, tofu or beans—it doesn’t matter which you pick—all are protein-rich. Gram for gram, protein will keep you feeling fuller longer compared to carbohydrates and fat (read: help keep those midnight snack attacks at bay). And don’t forget about low-fat dairy: recent research, published in the Journal of Nutrition, found that the protein in dairy (called whey protein) may help ward off weight gain and help build lean body mass.