Fiber is a substance in plants. Dietary fiber is the kind you eat. It is in fruits, vegetables and grains. It is the part of the plant that your body can't digest. Yet it is an important part of a healthy diet. It adds bulk to your diet and makes you feel full faster, helping you control your weight. Fiber helps digestion and helps prevent constipation.

You can get fiber from whole grains, beans, nuts, fruits and vegetables. You should add fiber to your diet slowly. Increasing dietary fiber too quickly can lead to gas, bloating and cramps.