Leaner teens compensate for fast-food meals

The appetites of teenagers can seem to know no bounds, especially when it comes to fast food. Although some adolescents can indulge with few ill consequences, others start packing on the pounds.

New research suggests an explanation.

Not only do slender teens eat less than their heavier counterparts, they also compensate for their fast-food binges by eating less later in the day. Overweight teens maintain their usual food intake even after a 1,500-calorie fast-food lunch, according to a study published in the June 16 issue of the Journal of the American Medical Assn.

“Certainly, the findings provide a basis for how fast food could promote excessive weight gain,” said the study’s lead author, Cara Ebbeling, an obesity researcher at Children’s Hospital Boston.

She and colleagues gave 54 teens who regularly ate fast food an extra-large lunch in a food court. They told the teens to eat as much or as little as they wanted in an hour.

Some ate a nine-piece chicken nuggets meal and then got more. On average, the 13- to 17-year-olds consumed 61.6% of their daily required calories in one sitting; those who were overweight ate 400 calories more than their slender counterparts.

“Fast food promotes higher energy intake, and among people susceptible to being overweight, it’s going to be even more dramatic,” said Simone French, an epidemiology professor at the University of Minnesota.

In the second part of the study, researchers let the same teens strike out on their own to McDonald’s, Burger King, KFC, Wendy’s or Taco Bell. The participants were required to get one item with protein plus a side item, such as French fries or a soda.

Researchers found that the leaner teens ate less later in the day to make up for their high-calorie lunch. In the end, they consumed about as many calories as they did on days that they didn’t eat fast food.

But the overweight adolescents did not adjust their other meals and ate about 400 more calories on fast-food days.

Over time, those calories could add up. About three of four teenagers eat fast food at least once a week.

“If [the leaner teens] get into this pattern, what’s going to happen when they’re 25 and 35, they’re going to gain weight too,” said French, who was not associated with the study. “I think it’s a risk factor for obesity.”

Ebbeling said she did not know what caused the overweight teens to keep eating or whether adults followed the same pattern.

“I think our findings serve to strengthen the argument for decreasing marketing to children, eliminating fast food in schools and also promoting healthful eating through nutritional information campaigns,” she said.