Scientists have released a commentary published in the International Journal of Obesity that proclaims that high-fructose corn syrup is not uniquely responsible for the increase in obesity, but it seems unlikely that the flavorful debate will be put to rest.

Written by James Rippe from the USDA, John Foreyt from Baylor College, and Theodore Angelopoulos from the University of Central Florida, the paper systematically analyzes and repudiates a theory put forth in a 2004 study that said that high-fructose corn syrup bears the brunt of the responsibility for the obesity epidemic in the United States and worldwide.

According to the paper, high-fructose corn syrup was developed in the mid-1960s. Because it is considered cheaper and sweeter than sucrose, or regular old table sugar, it was widely embraced by food and beverage makers. High-fructose corn syrup was used widely from 1970 to 1999, until use began declining. Today, sugar is eaten far more often than high-fructose corn syrup, at a proportion of 9 to 1.

The paper refers to several studies that attempted to find a link between obesity and high-fructose corn syrup, and high-fructose corn syrup and sugar are absorbed identically through the gastrointestinal tract. The paper also points out that "there are epidemics of obesity and diabetes in areas where there is little or no HFCS available such as Mexico, Australia, and Europe."

If the paper sounds like a rebuttal of sorts, that's because it is. Dr. Rippe received research grants and consulting fees from a variety of companies like ConAgra, Kraft Foods, and the Corn Refiners Association. Dr. Foreyt is a member of the scientific advisory panel of the Corn Refiners Association.

But the Corn Refiners Association is right to be on its toes. Citizens for Health, a non-profit organization that bills itself as the "voice of the natural-health consumer," received $300,000 from the sugar industry to attack high-fructose corn syrup as an alternative sweetener. Citizens for Health previously successfully lobbied the FDA to strike down the corn industry's term of "corn sugar" in advertisements. The FDA said that sugar was a solid, and syrup was a liquid. On its website Food Identity Theft, Citizens for Health says, "[Scientific] evidence shows that consuming HFCS might lead to health problems, including obesity, childhood diabetes, high blood pressure and heart disease."

That may or may not be true. Many scientists are pushing for sugars to be classified into different categories. Fructose, indeed, seems to be a problem - the sugar, which makes up half of table sugar and high-fructose corn syrup, is metabolized solely by the liver, while glucose can be metabolized by all the organs. Research does seem to indicate that the bombardment of the liver with fructose can lead to excess internal fat, insulin resistance, diabetes, and heart disease. Additional science in animals has found that fructose can reduce the body's sensitivity to leptin, which tells the body to stop eating.

According to the Corn Refiners Association's website Sweet Surprise, high-fructose corn syrup is not actually high in fructose, contrary to what its name indicates. And the FDA has approved that the liquid is safe at up to 55 percent fructose, slightly higher than table sugar's allowance of 55 percent fructose.

However, a 2010 study in Obesity found that some of the most popular soft drinks, like Coke and Sprite, use high-fructose corn syrup with up to 65 percent fructose. The corn industry has scoffed at attempts to identify the percentage of fructose in high-fructose corn syrup in foods, calling it a scare tactic.

The Corn Refiners Association had $27.3 million in revenue and spent $27.6 million in expenses in 2010, the last year for which data is available. The Sugar Association had $2.4 million in revenue and spent $2.7 million in expenses in 2010. Revenue increased to $4.2 million last year, and expenses rose to $4.3 million last year.

It is unlikely that there is any one particular cause for obesity, as electricity, grilled food, and antibiotic use have all been linked to the condition. Ultimately, the debate will continue to rage on.

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