Dietary fiber isn't important just to treat constipation. Populations that consume more dietary fiber have less chronic disease. In addition, intake of dietary fiber has beneficial effects on risk factors for developing several chronic diseases. The American Dietetic Association recommends that you consume 14 g of fiber for every 1,000 calories you eat -- that's about 25 g for adult women and 38 g for adult men. Most adults in the United States take in only about 15 g per day, so it's important to increase your consumption of high-fiber foods such as whole grains, legumes, fruits, and vegetables. And if your doctor recommends a fiber supplement, it's probably a good idea.