Oatmeal is both filling and full of energy. It is packed with soluble fiber, keeping you full longer and improving your digestive system. Oatmeal is also a great source of complex carbohydrates. These are broken down slowly by the body, keeping you feeling great for hours. Top your oatmeal with delicious additions, like cinnamon and nuts. Stay clear of adding a ton of sugar to your breakfast oatmeal. This can make you crash later. Instead, sweeten it naturally with fruit.