High fructose corn syrup not completely to blame for rise in obesity

By Karen Collins - American Institute for Cancer Research | Monday, November 24, 2008 11:48 AM PST ∞

According to a USDA report released this year, available calories from all forms of added sugars increased 17 percent from 1970 to 2006. The dramatic rise in obesity is the principal concern about sugar consumption among health professionals, but sugar's impact on development of diabetes, dental cavities and other health problems is also an issue.

But can sugar itself ---- even the much-maligned overuse of high-fructose corn syrup  ---- take all the blame? Or is an increase in overall calorie consumption what's really at the heart of this debate?

The rise in sugar consumption in the U.S. in the past three decades includes the use of table sugar, cane and beet sugar, honey, molasses and other syrups, as well as high fructose corn syrup and other corn sweeteners like glucose and dextrose. Many point to the introduction of low-cost high fructose corn syrup in the 1960s (created by converting some of the glucose in corn to much sweeter fructose molecules) as the beginning of the American sugar rush.

While an increase in sugar seems to correspond to the rise in obesity, that's not the whole story: Total calories from all food sources also increased by 520 calories a day from 1970 to 2006. Although the increase in sugar, high fructose corn syrup and other sweeteners played a role, added calories from fat and grain products actually account for even larger portions of our increased calories. Americans clearly need to reduce our excessive calorie consumption, and reducing added sugars is just part of that.

But if we need to cut back on added sugars, is there any difference between old-fashioned table sugar and the high fructose corn syrup now so common in commercial foods? In short, no. In fact, when the American Medical Association issued a statement earlier this year that encouraged limiting consumption of all calorie-containing sweeteners, it did not support specific warnings on high-fructose corn syrup.

Much of the debate surrounding high fructose corn syrup focuses on differences in the metabolic effects of glucose and fructose, the two simple sugars that combine to make the product. But both table sugar (sucrose) and high fructose corn syrup are composed of nearly equal amounts of fructose and glucose. Since sucrose is easily broken down in the digestive tract to the two simple sugars, both high fructose corn syrup and table sugar seem to result in absorption of similar amounts of fructose and glucose.

A healthy diet will always include some sugar, because it naturally occurs in many nutritious foods like fruit and milk. The key is to limit added sugars of all types, rather than focusing on table sugar (sucrose) versus high fructose corn syrup.

Guidelines from the Institute of Medicine suggest that added sugars can supply up to 25 percent of our daily calories. But this allows for up to 125 grams of added sugar a day on a 2,000 calorie diet ---- equivalent to 500 calories and almost 2/3 cup of sugar. Many nutrition experts contest this figure and recommend that no more than 10 percent of daily calories come from refined sugars. In fact, USDA dietary patterns show that after we meet our nutritional needs, most people have room for only 150 to 350 total "discretionary calories" (calories from "treats" that don't supply much nutritionally, such as sweets and alcohol).

Even the lower figure cited by the USDA would allow up to 22 teaspoons of added sugar if all discretionary calories were spent on sugar-sweetened soft drinks (the largest source of added sugars in the U.S. diet) and other sweets.

While that may sound like a lot, check the Nutrition Facts panel on food labels to see how quickly it adds up. You'll often find one or two teaspoons of added sugar (4 to 8 grams) in each serving of pasta sauce, white bread, hamburger rolls, ketchup and soup, with even larger amounts in cereal, yogurt and desserts.

Further research may provide additional guidance. For now, if we avoid sugary drinks and choose less processed foods, we can cut excess sugar and calories to help with weight control and have room for more high-nutrient, health-promoting foods as well.

Karen Collins is a registered dietitian who writes for the American Institute for Cancer Research. Visit www.aicr.org.