A wide range of foods, including peanuts, peanut butter, lentils, peas, garbanzo beans, kidney beans, pinto beans, and more are a part of the legume family. They contain both protein and fiber. "Not only do legumes require your body to burn a greater number of calories to digest [due to their high protein content], legumes also contain fiber, which helps feed your 'good' gut bacteria, [thereby] helping [to] improve the environment for your gut," Dr. Zenhausern told POPSUGAR.