Efforts to bulk up and tone muscles are common among teens, new research suggests.

According to the study findings, about 35 percent of boys and 21 percent of girls in middle and high school said they had used protein powder or shakes during the last year to bulk up or tone their muscles. Six percent of boys and 4.6 percent of girls said they had tried steroids. And 10 percent of boys and 5.5 percent of girls said they had used some other muscle-boosting product such as creatine.

That's not all youngsters are doing to build muscle. About 68 percent of boys and 62 percent of girls admitted they had altered their eating  habits, and 91 percent of boys and 80 percent of girls said they had increased the amount of exercise they did. Although these last two changes could be potentially healthy, the teenagers could also have modified their diets or exercise regimens in an unhealthy way, researchers said.

For example, substituting protein shakes for meals is not a healthy choice because it means teens are “missing out on the additional nutrients and other benefits of eating real food,” explained study researcher Marla Eisenberg, an assistant professor of pediatrics at the University of Minnesota. And teens who engage in excessive or compulsive exercise or eating behaviors could be at risk for serious conditions down the road, the researchers said.

Such behaviors “could point to body image problems that are analogous to the desire to be very thin, which we've been seeing in adolescents for many years,” Eisenberg said.

Overall, the study findings suggest that, “muscularity is an important component of body satisfaction for both genders,” the researchers said.

However, because the study was conducted in just one state, the findings might not apply to all teenagers, the researchers explained.

Previous studies have suggested around 10 percent of teen boys and 8 percent of adolescent girls use protein supplements, and 4 percent of boys and 2 percent of girls use steroids, but the prevalence of more general muscle-building behaviors, such as changing diet, was not known.

In this study, Eisenberg and colleagues analyzed information from about 2,800 students in 20 middle and high schools in the Minneapolis/St. Paul area.

The take-home message? Pediatricians should counsel their young patients about appropriate ways to increase muscle mass through exercise and nutrition, and teach them about the potential dangers of muscle-enhancing products, the researchers said. The focus should be on fitness and overall health rather than being ripped, they added.

The study is published today (Nov. 19) in the journal Pediatrics.

Pass it on: A preoccupation with muscle-building is common among teens.

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