We don't eat enough fiber. On average, we get less than half of what we need of this nutrient that can lower cholesterol, prevent constipation, and improve digestion. Most whole grains are a great source of fiber. Start at breakfast: Look for whole-grain cereal or oatmeal with 3 or more grams of fiber per serving. Add fruit and you'll be on your way to the daily goal of 38 grams for men and 25 grams for women.

Any type of fresh fruit is a healthy snack. But when it comes to fiber, all fruits are not created equal. One large Asian pear has a whopping 9.9 grams of fiber. Other high-fiber fruits include raspberries (4 grams per 1/2 cup), blackberries (3.8 grams per 1/2 cup), bananas (2.4 grams each), and blueberries (2 grams per 1/2 cup). Pears and apples -- with the skin on -- are also high-fiber choices.

If you can't work another serving of fruits, vegetables, beans, nuts, or whole grains into your diet, consider eating a food enriched with fiber. It's easy to find cereal, snack bars, toaster pastries, pasta, and yogurt fortified with extra fibe