After softening the impaction, the physician may break up and remove part of the hardened stool by inserting one or two fingers in the anus. It is important to remember that about 90 percent of cases of constipation are not due to underlying diseases. The most common cause of constipation is a diet low in fiber found in vegetables, fruits, and whole grains and high in fats found in cheese, eggs, and meats. People who eat plenty of high-fiber foods become constipated less often. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines.
Insoluble fiber passes almost unchanged through the intestines.
The bulk and soft texture of fiber help prevent hard, dry stools that are difficult to pass. On average, Americans eat about 5 to 10 grams of fiber daily, short of the 20 to 35 grams recommended by the American Dietetic Association. Both children and adults eat too many refined and processed foods in which the natural fiber is removed. A low-fiber diet also plays a key role in constipation among older adults. They often lack interest in eating and may choose fast foods low in fiber.