Fiber - why, good sources and how much?

WHY
Dietary fiber from fruits and vegetables as part of an overall healthy diet, helps reduce blood cholesterol levels and may lower risk of heart disease. Fiber is important for proper bowel function. It helps reduce constipation and diverticulosis. Fiber-containing foods such as fruits help provide a feeling of fullness with fewer calories.
GOOD SOURCES
Beans, bran, fruits and vegetables are generally a good source of fiber.
The top bean choices are cooked versions of navy beans, kidney beans, split peas, lentils, black beans, pinto beans, chick peas - in general any kind of legumes and beans are good sources of fiber.
Lima beans, cooked green peas, artichoke, sweet potato, spinach, brussel sprouts, broccoli, turnip greens, collard greens, okra, pumpkin are top vegetable fiber sources
Asian pear, pear, raspberries, blackberries, guava, oranges, prunes, figs and dates are top fruit sources of fiber.
Besides these bran cereal, whole wheat english muffin, cooked bulgur, whole wheat pasta, almonds are all good sources of fiber.
HOW MUCH
The food pyramid recommends 25 gms per day of fiber.
Refer to the Dietary guidelines for americans http://www.health.gov/dietaryguidelines/dga2005/document/html/appendixB.htm#AppB8
for more details on how much to eat for each of these foods.