The debate over the benefits of dietary fiber has lingered for many decades. By itself, it doesn’t provide any vitamins and minerals and is not broken down or absorbed in the digestive tract as are other nutrients. However, fiber is found in foods such as vegetables, fruits, beans (legumes) and grains that do provide us with the essential nutrients we need. So it rides along with these nutrients.
Fiber is classified as soluble and insoluble but most foods contain a mixture of both types.
Good sources of soluble fiber: legumes, prunes, apricots, raisins, oranges, bananas, oats, apples, eggplant, flax seed
Good sources of insoluble fiber: wheat bran, whole-wheat bread, broccoli, corn, eggplant, apple skins, nuts and seeds
How much do we need? For young men the recommendation is 38 grams/day and for young women, 25 grams a day. Consider this example:
“Eating a bowl of Raisin Bran with a 1/2 cup of strawberries for breakfast, a sandwich on whole wheat bread with lettuce and tomatoes and an apple for lunch, eggplant Parmesan for dinner, and popcorn for a snack will provide about 25 grams.” Smolin and Grosvenor, Nutrition, Science and Applications, Third Edition.
Based on diet analyses I have seen, the average daily intake is only about 9-11 grams a day.
So you can see that it is not easy to get enough fiber that is best explained in the linked article below.
What does it actually do for us?