Women who eat lentils at least twice a week are 24 percent less likely to develop breast cancer than women who eat them less than once a month, studies show. Lentils keep blood sugar steady, and just a quarter cup of these miniature legumes provides 13 grams of protein, 11 grams of fiber, and 5 milligrams of iron. Try them in soups or salads, or as a tasty side.