Starch is the preferred carbohydrate, since digestion depolymerizes it to pure glucose which can be used directly by cells.

Cane sugar, a disaccharide, is split by digestion into its constituent glucose and fructose molecules, and the latter must be further processed by the liver. It is 50% fructose.

High fructose corn syrup is 55% fructose.

A variety of other sugars, such as maltose and lactose occur naturally in a variety of foods. However, they are in low enough concentrations to not be a health problem.