Consumption of high-fructose corn syrup is widely known to cause weight gain, but surprising new research shows it may cause people to be less active as well.

In the last 40 years, fructose, a simple carbohydrate derived from fruit and vegetables, has dramatically increased in American diets thanks to the addition of the inexpensive sweetener high-fructose corn syrup. Fructose currently accounts for 10 percent of the calories Americans eat.

Researchers at the University of Illinois Beckman Institute for Advanced Science and Technology recently conducted an animal study in which they compared diets containing fructose versus one with another type of sugar, glucose, in mice.

They fed both groups of mice a diet sufficient in calories but gave one group 18 percent of calories from fructose and the other from glucose, an amount that mimicked the sugar intake typical of adolescent U.S. males.

After two-and-a-half months, the researchers discovered that the mice on the fructose diet not only gained more weight and body mass but were less active.

Although the researchers said they did not know why the animals on the fructose-fed diet moved less, but they speculated that this may be the reason why its consumption leads to weight gain even when calories are equal.