Carbohydrate, any member of a large class of chemical compounds that includes sugars, starches, cellulose, and related compounds. These compounds are produced naturally by green plants from carbon dioxide and water (see photosynthesis). Carbohydrates are important as foods; they supply energy and are used in the production of fats. They are also used in various forms in industry and commerce.
There are three main classes of carbohydrates. Monosaccharides are the simple sugars, e.g., fructose and glucose; they have the general formula (CH2O)n, in which n is an integer larger than