In a 2009 poll by the Vegetarian Resource Group, an advocacy organization, for example, 11% of girls ages 13 to 15 said they were vegetarian. A 2001 survey of more than 4,700 middle school and high school students in Minneapolis-St. Paul found that the typical young vegetarian was a nonblack female who was self-conscious about her weight.
On the plus side, studies show that vegetarian teenagers eat more fruits and vegetables and less saturated fat than non-vegetarian teens. A 2002 University of Minnesota study found that 26% of vegetarian kids ate the recommended number of servings of vegetables, for example, compared to 14% of non-vegetarians.
But unlike adults and older teens, younger vegetarian teenagers aren't necessarily thinner than meat-eaters. And as a group, they still have a long way to go to be truly healthy: Even though they're doing better than their peers, three-quarters of the vegetarians in the study still weren't getting their recommended daily produce.
Vegetarian teens also are more likely to show signs of an eating disorder. In a 2001 study, Neumark-Sztainer and colleagues found that 69% of vegetarian adolescents had used unhealthy weight control behaviors in the previous year, compared with 44% of their non-vegetarian peers. Nine percent of the vegetarians were told by a doctor that they had an eating disorder, which was triple the number of non-vegetarians who had been told the same thing.
In another study, published in April in the Journal of the American Dietetic Assn., Neumark-Sztainer and colleagues found that, among a group of 15- to 18-year-olds, 20% of current and former vegetarians reported that they had binged or performed other unhealthy eating behaviors, compared to 5% of those who had never been vegetarians.
"Our study does not show that becoming vegetarian leads to developing an eating disorder," says Neumark-Stzainer, author of the book " 'I'm, Like, SO Fat!': Helping Your Teen Make Healthy Choices About Eating and Exercise in a Weight-Obsessed World." But, she says, "I do think some teenagers choose to adapt a vegetarian diet because it is a socially acceptable way of restricting more foods. So, for some teenagers, becoming vegetarian may be a red flag for a more serious weight-related problem."
If your teenager announces that she or he is now a vegetarian or vegan, the first step, Neumark-Stzainer says, is to ask why. Look for other concerning behaviors, such as over-exercising, skipping meals, talking a lot about weight or withdrawing from the family. If you see a worrisome pattern, talk to your teen, help her or him to execute a vegetarian diet in a healthy way and, if necessary, seek help. Eating disorders are serious diseases.