Quarter of American teens misperceive their weight and often have unhealthy habits

Nearly a fourth of American teenagers misjudge their weight and they often avoid a healthy diet and physical activity based on weight misperceptions, says a new study from Ball State University.

"Adolescent Body Weight Perception: Association with Diet and Physical Activity Behaviors" is an analysis of about 12,000 teens (ages 15-17) who participated in the Youth Risk Behavior Survey. The study, which was posted today by the Journal of School Nursing, found that nearly a fourth (22.9 percent) misperceived their weight; 11.6 percent believe they are overweight but aren't, and 11.3 percent weigh more than they should but think it's healthy and continually underestimate their weight.

"American adolescents who misperceive their weight are significantly more likely to engage in unhealthy dietary and food habits and are more likely to have sedentary lifestyles," said Jagdish Khubchandani, corresponding author and a health science professor at Ball State. "On the contrary, teenagers who have accurate perceptions of their weight practice healthier behaviors or avoid risky weight loss methods."

This is a significant finding, as the U.S. is currently witnessing high rates of obesity across all ages, Khubchandani said.

"Recent evidence also suggests that adolescent weight misperception is associated with obesity in adulthood," he said. "Early childhood interventions to promote appropriate weight-related perception and weight management could have a lasting impact on chronic disease burden, in addition to preventing unhealthy diet and physical inactivity in youth."

The study also found:

• Almost a third (31.8 percent) of adolescents were overweight and obese.
• Boys and girls who believed they were overweight but were not truly overweight were less likely to drink fruit juice or milk, eat fruits, or consume breakfast regularly.
• Physical activity behaviors also varied with weight perception. For example, both boys and girls who were truly overweight or only believed they were, had the lowest odds of engaging in physical activity for at least 60 minutes per day five days a week.
• Females were more likely to have misperceptions about their weight than males.

"Interestingly, weight misperception has also been linked with eating disorders that are a major cause of morbidity in young Americans," Khubchandani said. "School nurses and health teachers are uniquely poised to educate students and prevent weight misperception, eating disorders, and engage students in healthy behaviors.

"Regular exercise routines in youth also shape future physical activity behaviors. A variety of school-based and cost-effective interventions to enhance youth physical activity have been documented in the literature that can be implemented with youth in school setting."