Fiber has loads of benefits, including speeding up digestion, maintaining lung health and decreasing your risk of chronic heart disease. To maintain a healthy digestive system it's essential to eat enough fiber. For men that means as much as 38 grams of fiber a day and for women it's 25 grams. Incorporating the following foods will help. A high-fiber breakfast cereal is a good place to start. Look for cereals with at least 5 grams of fiber per serving and watch out for sugar.