Sorbitol is a type of carbohydrate called a sugar alcohol, or polyol, that contains a third of the calories as sugar is about 60% as sweet. Sorbitol naturally occurs in fruits and vegetables but is commonly produced from glucose through a process called catalytic hydrogenation or through the fermentation of fructose for commercial purposes as a sweetener. The glucose used is commonly derived from corn or potato. Sorbitol is not fully digested in the gastrointestinal tract and so it provides fewer calories than sugar. It is commonly used as a low-calorie sweetener and in low-carbohydrate foods, and can even be purchased as a laxative.