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Dieting Common Among High School Students

60% Have Tried to Lose Weight, Study Shows

By Miranda Hitti
WebMD Medical News

Reviewed By Brunilda Nazario, MD
on Tuesday, August 31, 2004

Aug. 31, 2004 -- Many Americans start dieting at a young age, but they don't always do so wisely, according to a study in the Journal of the American Dietetic Association.

Sixty percent of 10th graders surveyed at a Los Angeles-area public high school said they had tried to lose weight. Of those students, more than half said they "often diet to control their weight," write the researchers, who were led by Laura Calderon, DrPH, RD, associate professor at California State University.

Calderon's team surveyed 146 students enrolled in the high school's health classes. Both boys and girls took part. About 27% of the teens had a body mass index greater than 25. (BMI is an indirect measure of body fat. A BMI greater than 25 is considered overweight.)

Some of the teens' strategies may sound familiar.

Among the teen dieters, 34% ate small portions, about 31% counted calories, and almost 42% counted fat grams. Nearly 65% said they sought out low-fat foods.

Then there were the extreme tactics, like skipping meals, which 44% of the student dieters had tried.

That's a bad idea. Skipping meals hasn't been shown to help lose weight.

Bad Dieting Behaviors

All too often, teens have misguided ideas about dieting and unhealthy dieting behaviors. For instance, they tend to cut calories ruthlessly, reducing the amounts of fats in their diets without compensating by increasing the amounts of fruits and vegetables they eat. They also attempt to lose weight by vomiting or using laxatives and over-the-counter diet pills, say the authors.

They also start too young, which can effect growth and development -- especially in girls. Of the female dieters in this study, nearly 36% said they started dieting by age 12, almost 85% by age 13, and the rest by age 15. More female students than male students had tried to lose weight at some time.

And while too many teens are overweight, their leaner classmates sometimes diet needlessly. About 67% of girls with a normal BMI (between 18.5 and 25.0) reported dieting, as did almost 8% with a BMI under 18.5, which is considered underweight.

None of the males whose body mass index was under 18.5 said they had dieted, but about 23% with a normal BMI said they had.

Ethnic differences also counted. Hispanics were the most likely to have dieted, followed by whites and Asians in equal numbers, with blacks last.

For any teen, dieting can be risky. Their physical development requires appropriate nutrition, and dieting has been called the most important predictor of new eating disorders.

All the more reason to start teaching safe weight control practices early, say the researchers. They want to see such efforts start by the seventh grade - early enough to catch most potential dieters before they take matters into their own hands.

SOURCES: Calderon, L. Journal of the American Dietetic Association; September 2004; vol 104: pp 1369-1374. News release, American Dietetic Association.