What's So Bad About High-Fructose Corn Syrup?

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"It’s natural, nutritionally the same as table sugar and has the same number of calories," say ads for high-fructose corn syrup (HFCS). Others call the sweetener "a growing health hazard," "naturally evil," and worse. For now, the naysayers seem to be winning: the number of foods flaunting "No HFCS" labels is rising steadily. Even Snapple and Pepsi recently launched new beverages sans HFCS. But what’s the truth about HFCS? Here’s what we found when we looked at the science.

Is HFCS the main culprit in the obesity epidemic?

The theory sounded logical in 2004, when an article in the American Journal of Clinical Nutrition proposed it. The study’s authors — including Barry Popkin, Ph.D., director of the University of North Carolina, Chapel Hill’s Interdisciplinary Obesity Center — pointed out that from 1970 to 1990 Americans’ intake of HFCS increased by more than 1,000 percent. The researchers also noted that, during that same time, the proportion of Americans who were overweight or obese increased from about half to two-thirds.

Singling out HFCS turned out to be unjustified, Popkin now admits. "Dozens of human studies on HFCS and energy intake and weight change show that our hypothesis was wrong." The American Medical Association came to a similar conclusion last June, when it announced that "high-fructose corn syrup does not appear to contribute more to obesity than other caloric sweeteners."

So why are so many more Americans overweight? For one, we’re eating more. Period. The latest U.S. Department of Agriculture estimates show that, since 1970, our daily calorie intake has grown by a whopping 24 percent. Sweetened beverages have added a huge quantity of calories to our diets. "More than 450 of a person’s daily calories come from beverages, 40 percent from soft drinks or fruit juices," says Popkin. Studies show that when we consume calories in liquid form our bodies don’t acknowledge them the way they do those from solid food and we don’t cut our food intake later. So should we blame HFCS, since it sweetens most sodas and sweet drinks? That’s guilt by association, not a direct cause, says Popkin. "Sugary beverages are the culprit, and whatever form the sugar is in does not matter."

Do studies show that HFCS amps up your appetite?

People often confuse HFCS with plain fructose and, in fact, a number of studies in animals and humans suggest that consuming pure fructose may not satisfy hunger the same way pure glucose does.

Both fructose and glucose trigger reactions in the body that eventually lead to feeling full, says Kathleen Melanson, Ph.D., R.D., a professor of nutrition and food sciences at the University of Rhode Island. But glucose does this more efficiently. When you consume glucose, the pancreas releases insulin, which, in turn, causes an increase in leptin, a hormone that tells the brain we’ve eaten enough. Glucose also blunts the effects of ghrelin, a "hunger hormone" that makes us want to eat more. Pure fructose doesn’t activate these same "fullness" cues, explains Melanson.

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