Consumption of simple sugars (monosaccharides) such as fructose has risen markedly in the American diet since the 1970s. This is due in large part to the development of high fructose corn syrup (HFCS), which is produced by the enzymatic conversion of glucose (also known as dextrose) to fructose (Hanover and White 1993). The most popular form of HFCS is comprised of 55% fructose (Hanover and White 1993; Park and Yetley 1993). Compared to sucrose, fructose is preferred by food manufacturers for several reasons: fructose is sweeter, and HFCS can be easily produced at a low cost. It has also been found to enhance flavors of foods such as caramel and chocolate (Park and Yetley 1993; Bray, Nielsen et al. 2004).

Fructose comprises approximately 8% of the total daily energy intake in the United States (Park and Yetley 1993; Havel 2005). This percentage includes both naturally occurring sources, such as fruits and vegetables, and added sources such as HFCS, sucrose (50% fructose), concentrated fruit juices, andcrystalline fructose. Food consumption surveys conducted in 2006 indicate that teenagers (ages 12-18 years) consume the most fructose. Approximately 12.17% of their total energy intake is from fructose, the highest percentage of which comes from non-alcoholic, non-100% juice beverages (NHANES, unpublished). The per capita use of HFCS ncreased from 0.23 kg in 1970 to 28.4 kg in 1997 (Putnam, Allshouse et al. 2002).