The best high-fiber foods to help with constipation are whole-grain breads, cereals and pastas, according to WebMD. Other helpful high-fiber foods are seeds and the skins of many fruits and vegetables.
Cereal fibers have cell walls that resist digestion, retain water and thus act as natural laxatives, as described on WebMD. There are two types of fiber: soluble and insoluble. Soluble fiber slows digestion and aids the body in absorbing nutrients, while insoluble fiber adds bulk to stool and aids in passing it through the intestines. Other foods that help alleviate constipation are the fiber found in citrus fruits and legumes because they encourage the growth of colonic flora, which increases the stool weight and the amount of bacteria in the stool. The growth of certain bacteria in the colon may help promote a healthy intestine.
Women should consume about 21 to 25 grams of fiber daily, and men should consume about 30 to 38 grams of fiber daily. Americans only consume about 15 grams of fiber daily, which is much less than the body requires, according to WebMD. It also recommends eating at least nine servings of fiber-rich fruits and vegetables each day such as apples, oranges, broccoli and carrots.