Corn sweeteners likely culprit.

• Position: Obesity

By coupling extensive Department of Agriculture food consumption data and their own analyses with previous research, nutritionists have concluded that high-fructose sweeteners made from corn are partially responsible for the growing national obesity epidemic. Introduction of the sweeteners, which are cheaper to produce and use in food manufacturing than cane and beet sugars, correspond closely time-wise with the epidemic's start, the researchers claim. Several other biological factors associated with high-fructose corn sweeteners appear to boost their negative effects on Americans' waistlines as well.

"Body weights rose slowly for most of the 20th century until the late 1980s," says George A. Bray, Boyd professor at the Louisiana State University System's Pennington Biomedical Research Center, Baton Rouge. "At that time, many countries showed a sudden increase in the rate at which obesity has been galloping forward."

The usual suspects for burgeoning fatness in this country have been the increase in food intake and a drop in physical activity. To examine the potential role of excess eating, Bray analyzed USDA consumption records from 1967-2000. "In examining this data, the importance of the rising intake of high fructose corn syrup was obvious. It did not exist before 1970. From that point, there was a rapid rise in this country in...