Grains are divided into: Whole Grains and Refined Grains. Whole grains contain the entire grain kernel ― the bran, germ, and endosperm. Example: whole-wheat flour, bulgur (cracked wheat), oatmeal, whole cornmeal, and brown rice. Refined grains have been milled, which removes the bran and germ. This process removes dietary fiber, iron, and many B vitamins. Example: white flour, de-germed cornmeal, white bread, and white rice.
Thus, whole grains provide much more nutrition.