" carbohydrate controls insulin; insulin controls fat storage. Carbohydrates are not used as structural components in the body; instead they are used only as a form of fuel, whether burned immediately while passing by different organs and muscles or stored for later use. All forms of carbohydrates you eat, whether simple or complex, are eventually converted into glucose, which the brain, red blood cells and nerve cells generally prefer as a primary fuel. "

― Mark Sisson , The Primal Blueprint: Reprogram Your Genes for Effortless Weight Loss, Vibrant Health, and Boundless Energy