Dietary fiber consists of non-digestible carbohydrates and lignin that are intrinsic and intact in plants. This includes plant non-starch polysaccharides (for example, cellulose, pectin, gums, hemi-cellulose, and fibers contained in oat and wheat bran), oligosaccharides, lignin and some resistant starch. (Source: Food and Nutrition Board)

• Soluble fiber dissolves in liquid to form a gel-like substance. Sources of soluble fiber are oats, legumes (beans, peas and soybeans), apples, bananas, berries, barley, some vegetables and psyllium (fiber supplements).
• Insoluble fiber is "nature's broom." It increases the movement of material through your digestive tract and increases your stool bulk. Sources of insoluble fiber are whole wheat foods, bran, nuts, seeds, and the skin of some fruits and vegetables