Fructose is sometimes called fruit sugar because of its presence in fruit. Fructose is a monosaccharide--a single sugar molecule consisting of six carbon atoms, six oxygen atoms and 12 hydrogen atoms. It can be absorbed quite quickly into the blood stream from your small intestines. In addition to fruit, fructose may be present in your menu as honey or syrup or as the food additive high-fructose corn syrup (found in many beverages, salad dressings, and so on). Fructose absorption can be very rapid if the source is high-fructose corn syrup. Absorption from whole fruits is less rapid because of the presence of fiber and other phytonutrients in fruit.