When it comes to fast food, lean teens are as likely as their overweight counterparts to eat too much. But trim adolescents do something that overweight teens do not -- eat less at other meals to cope with their overindulgence, according to a study reported in the June 16 issue of the Journal of the American Medical Association.

The study found that fast food consumption has increased rapidly since the 1970s among adolescents from all socioeconomic and racial and ethnic groups across the United States as an estimated 75 percent of adolescents eat fast food one or more times per week.

Cara B. Ebbeling, Ph.D., from Children's Hospital in Boston, and her colleagues have linked the rising fast food consumption with the escalating obesity epidemic given the enormous portion sizes, excessive refined starch, added sugars and fat; and inadequate dietary fiber of fast food.

The researchers conducted two studies to evaluate the effects of fast food in 26 overweight and 28 lean teens between the ages of 13 to 17 years who reported eating fast food at least one time per week.

In one study, participants were fed extra large fast food meals in a food court and instructed to eat as much or as little as desired during the one-hour meal. In the second study, researchers assessed how much food was eaten during a two-day period in which teens consumed fast food and a two-day period in which they did not.

The researchers found that the overweight participants consumed more on days with fast food than without it, in contrast to the lean participants who consumed virtually the same amount on both days.

"This observation suggests that overweight individuals do not compensate completely for the massive portion sizes characteristic of fast food today," the authors concluded.

Other sources: JAMA. 2004; 291:2828-2833