Dietary fiber has demonstrated benefits for health maintenance and disease prevention and as a component of medical nutrition therapy. Except in certain therapeutic situations, dietary fiber should be obtained through consumption of foods. In addition to fiber, minimally processed fruits, vegetables, legumes, and whole and high-fiber grain products provide micronutrients and nonnutritive ingredients that are essential components of healthful diets. Dietary fiber consists of structural and storage polysaccharides and lignin in plants that are not digested in the human stomach and small intestines. Dietary fiber includes polysaccharides, oligosaccharides, lignin, and associated plants substances. Dietary fibers promote beneficial physiological effects including taxation, and/or attenuation of blood cholesterol and/or blood glucose levels. A fiber-rich diet is lower in energy density. It often has a lower fat content, relatively larger bulk volume, and higher micronutrient content, all of which have beneficial health effects. By encouraging people to eat fiber-rich plant foods, dieteticians can have a significant impact on the prevention and treatment of obesity, cardiovascular disease, and type 2 diabetes, as well as constipation. Consumption of dietary fibers that are viscous lowers blood cholesterol levels and helps to normalize blood glucose and insulin levels, making these kinds of fibers part of the dietary plans to treat cardiovascular disease and type 2 diabetes. Fibers that are incompletely or slowly fermented by microflora in the large intestine promote normal taxation and are integral components of diet plans to treat constipation and prevent the development of diverticulosis and diverticulitis. Recommendations for adult dietary fiber intake generally fall in the range of 20 to 35 g/day. Others have recommended dietary fiber intakes based on energy intake, 10 to 13g of dietary fiber per 1000 kcal. The recommendation for children older than 2 years is to increase dietary fiber intake to an amount equal to or greater than their age plus 5 g/day and to achieve intakes of 25 to 35 g/day after age 20.