Among teens in one Los Angles public school, 60 percent reported dieting at some point in their lives - primarily before the age of 14 - and many said they skipped meals or vomited to control their weight.

In fact, 15 percent of these weight-conscious teens said they went on a diet before they turned 11 years old, according to a team of California and Texas researchers.

“Because dieting practices has been considered a risk factor for the development of an eating disorder, this behavior deserves attention,” according to study author Dr. Laura L. Calderon, of California State University, Los Angeles and her colleagues.

They studied dieting behaviors among 146 tenth graders who attended an urban, multiethnic high school in the Los Angeles area. About a third were male, and most were 14 or 15 years old.

About 27 percent of the study group had a body mass index - a measure of weight in relation to height - greater than 25, which is classified as overweight, the researchers report in the Journal of the American Dietetic Association.

Almost three-quarters of males in this at-risk BMI group said they had dieted, in comparison to about one quarter of females. Among females, dieting was most commonly reported among those in the normal-weight range, a finding that echoes results of other studies, the report indicates.

Many of the teens who reported ever dieting said their strategy included limiting the portion size of their food, counting the number of calories in the food they consumed or counting grams of fat. In fact, nearly 65 percent of the dieters, males in particular, said they tried to eat low-fat foods.

Many students also reported skipping meals as a weight control technique, although research has shown this strategy to be ineffective, the authors note. Twenty percent of males and 18 percent of females also said they had vomited after a meal at least once and up to 13 percent said they had used an over-the-counter diet aid.

Citing the negative health effects of over-the-counter supplements like ephedra, which is also known as Ma huang, the researchers write that “high school students should be educated not only on the risk of dieting but also on the specific risks associated with various dieting behaviors and OTC diet aids.” Ephedra has been linked to an increased risk of heart attack and stroke.

Further, in light of the dieters’ young ages, “nutrition education regarding healthy eating and lifestyle habits, including safe vs. unsafe dieting practices, should begin by the seventh grade,” the authors conclude.

According to Dr. Laurel Sharmer, a certified health educator who was not involved in the study, it is not surprising that such a high proportion of teenagers have attempted dieting. “What’s of concern,” she said, “is that they’re not succeeding.”

In her experience as a community health professor at the State University of New York at Potsdam, Sharmer said she has also noticed a change among her students with regard to dieting practices. Years ago, it was the thin and frail anorexic-looking girls asking for advice on how to lose weight, she said, now it’s the girls who are very overweight. “A happy medium is hard to find,” she told Reuters Health, citing the increased prevalence of obesity.

In light of the findings, Sharmer advises parents to not only get rid of the soda pop, potato chips, corn chips and other high-fat snack foods in the house, but to also “sit down and talk with your kids about all the empty calories that are in those foods.”

SOURCE: Journal of the American Dietetic Association, September 2004.