Over the past 30 years, fast food consumption among adolescents has increased significantly. Likewise, the population of overweight and obese adolescents has increased: In 2002 an estimated 16% of children and adolescents were overweight, up from 6% in 1976.

Whether or not fast food consumption has contributed to the increase in overweight and obesity is the subject of much debate. Previous research has shown that fast food intake is directly associated with a higher total calorie intake and lower overall diet quality, but not all studies have found a connection between fast food consumption and body weight.

Most children—an estimated 75%—eat fast food on a regular basis, but most are not overweight. A new study in the June 16, 2004 issue of the Journal of the American Medical Association set out to determine why, among those who eat fast food, some children become overweight and others don’t. What they found was that while all adolescents were prone to overeating, lean adolescents compensate for the extra calories consumed during their fast food meals.

About the Study

This study included 54 adolescents between the ages of 13 and 17 who reported eating fast food at least once per week. Of these adolescents, 26 were overweight and 28 were lean. The study consisted of two phases, with 51 participants staying on for the second phase.

  • In the first phase, the researchers provided the adolescents with “extra large” fast food meals in a food court, and instructed them to eat as much (refills were readily available) or as little as they desired over the course of an hour.
  • Then, in the second phase, the researchers conducted four separate phone interviews with the participants to find out about their total food intake and physical activity on two days that included a fast food meal, and two days when fast food was not consumed.

The researchers compared the calories consumed on all the fast food days and non-fast food days for lean and overweight adolescents.

The Findings

The overweight and lean participants were similar with respect to sex, race, age, and height. Results from phase one showed that on average, the participants consumed 1652 calories from the fast food meal—accounting for more than 60% of their daily energy needs (in one hour!). Although all of the participants overate, those who were overweight ate more than those who were lean: 1860 calories versus 1458 calories.

An interesting difference between the lean and overweight individuals was observed in the second phase of the study: Overweight participants consumed an additional 400 calories on fast food days than non-fast food days (2703 versus 2295), while lean participants averaged about the same number of calories on both days (2575 versus 2622). Physical activity level, however, was similar among all participants and on both types of days.

How Does This Affect You?

This study suggests that lean adolescents are more likely to compensate for the excess calories they consume from fast food meals by eating less at other meals than overweight adolescents. But it also shows how easy it is to consume excess calories when presented with today’s standard fast food meal, which in this study led to overeating among all the adolescents—regardless of weight.

Another study, published in the same edition of the Journal of the American Medical Association , analyzed national data from 1999 to 2002 and found that the prevalence of obesity among adults and overweight among children shows no signs of decreasing. According to this data, nearly one-third of children between the ages of 6 and 19 are overweight or at risk for being overweight. What’s particularly disturbing about this data is that overweight adolescents have an extremely high risk of becoming obese adults.

Although fast food may be only one part of the equation, given its popularity among adolescents, it’s clearly one of the major factors contributing to over-consumption of calories and subsequent weight gain. Furthermore, it’s not just the excess calories in fast food that’s concerning, but also the overall poor nutritional quality of fast food, which tends to be low in fruits, vegetables, and whole grains, and high in saturated and hydrogenated fat.

While it’s unrealistic to try and completely avoid fast food, it should always be the exception, not the norm. You can promote healthful eating by restricting your child’s access to high calorie meals, packing healthful snacks and lunches, and of course, leading by example. Every parent wants the best education possible for his or her child. Why not the best health?