Oatmeal is a great source of fibre and complex carbohydrates, both of which help the body maintain normal blood sugar levels. It also contains folate and potassium. Oatmeal can be prepared with whole grains or rolled oats, with the latter being rich in fiber and lower in calories. Oatmeal is also a good source of protein. Try to avoid refined versions of the food, as they are typically devoid of the germ and bran.