Whole grains are cereal grains which retain the bran and germ as well as the endosperm, in contrast to refined grains which retain only the endosperm. Whole meal products are made from whole grain flour.
Common whole grain products include many breakfast cereals, oatmeal, popcorn, brown rice, whole wheat flour, and whole wheat bread. Common refined grain products include white rice and white bread, as well as most hominy and pasta.
Whole grains are often more expensive than refined grains because their higher oil content is susceptible to rancidification, complicating processing, storage, and transport.
Similar to the distinction between whole and refined grains is that between whole pulses and refined dal.
Whole grains are believed to be nutritionally superior to refined grains, richer in dietary fiber, antioxidants, protein (and in particular the amino acid lysine), dietary minerals (including magnesium, manganese, phosphorus, and selenium), and vitamins (including niacin, vitamin B6, and vitamin E). Manufacturers are sometimes required by law to fortify refined grain products to make up for the loss of vitamins and minerals.
The greater amount of dietary fiber, as much as four times that found in refined grains, is likely the most important benefit, as it has been shown to reduce the incidence of some forms of cancer, digestive system diseases, coronary heart disease, diabetes, and obesity. Some of these protective effects occur because carbohydrates from whole grains are digested and enter the bloodstream more slowly (as measured by the glycemic index).