Dietary fiber is the portion of food derived from plants that our body is unable to digest and absorb. These fibers include non amyloid polysaccharides (eg.: cellulose, hemicellulose, gums and pectin), oligosaccharides (e.g. inulin) or lignin. Vegetables, seeds, grain and some partially milled cereal also contain a type of starch which is resistant to digestion and absorption in the small intestine and therefore reaches the large intestine with its structure largely intact acting like other dietary fibers.
Dietary fiber is essential for the health of the body and although they don't provide energy, its consumption helps regulate the intestinal transit, prevents disease and may still be an important ally in weight loss.