Roughage is the portion of plant foods, such as whole grains, nuts, seeds, legumes, fruits, and vegetables, that your body can't digest. Roughage, or fiber, has long been recommended to help with digestive issues like constipation, but it also plays many other important roles in your body. For example, the roughage in plant foods can promote optimal gut health, help you manage your weight, and even reduce your risk of heart disease.