What Is the Glycemic Index of Fructose Corn Syrup?

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High-fructose corn syrup, often abbreviated as HFCS, is a man-made sweetener derived from corn. High-fructose corn syrup has become the most commonly used sweetener in processed foods in the United States, sweetening not just soda and candy but all types of condiments, baked goods, snack foods, soups and cereals. The glycemic index assigns a value to a food based on the amount of time it takes for the food to break down into glucose and be absorbed into cells, with a GI of 100 assigned to pure glucose, the most quickly absorbed form of sweetener.

Gycemic Index

The glycemic index of a food can vary depending on how it’s processed or prepared. The GI of high-fructose corn syrup, according to research reported in the September 1989 “Journal of the Formosan Medical Association,” is 73, but could vary depending on the exact fructose-to-glucose concentration in the product. A high GI index is considered over 70, while a GI below 55 is considered low.

Sweetener Differences

High-fructose corn syrup consists of fructose, the main sweetener in fruit and glucose. Sucrose, or table sugar, also contains both fructose and glucose but in equal proportions, while HFCS can contain slightly more fructose, 55 percent to 42 percent glucose and 3 percent other sugar molecules in HFCS 55. Another form of HFCS, HFCS 42, contains 42 percent fructose and 58 percent glucose. Fructose breaks down differently than other sugars and doesn’t trigger an insulin release. Insulin, normally released when you consume carbohydrates, helps cells absorb glucose from your blood. Insulin triggers leptin release, which signals that you’re full and should stop eating. Without this signal, you may eat more because you don’t get the signal to stop, registered dietitian Christopher Mohr states.


The GI of high-fructose corn syrup doesn’t vary significantly from other sugars, but some studies indicate that HFCS is more likely to cause weight gain than other sugars. Princeton researchers reported in the February 2010 issue of “Pharmacology, Biochemistry and Behavior” that rats fed HFCS were more likely to gain weight than rats fed a high sucrose diet. However, registered dietitian Jennifer Nelson of the Mayo Clinic states there’s no proof that HFCS is more likely to cause obesity than any other sweetener.


Americans now consume around 60 lbs. of high-fructose corn syrup per person during the year, according to Princeton University. During approximately the same time frame as the rise in the use of HFCS, the American obesity rate has risen to around 33 percent, the same source reports. Despite the similar GI to other sweeteners, HFCS may behave differently in your body. Considering the ubiquitousness of this product and the obesity rate of Americans, eliminating HFCS as much as possible may help control America’s weight problem, Princeton researchers suggest.