The role of social norms and friends’ influences on unhealthy weight-control behaviors among adolescent girls.

Dieting is common among adolescent girls and may place them at risk of using unhealthy weight-control behaviors (UWCBs), such as self-induced vomiting, laxatives, diet pills, or fasting. Research has suggested that social factors, including friends and broader cultural norms, may be associated with UWCBs. The present study examines the relationship between the school-wide prevalence of current weight loss efforts among adolescent girls, friends’ dieting behavior, and UWCBs, and investigates differences in these associations across weight categories. Survey data were collected in 31 middle and high schools in ethnically and socio-economically diverse communities in Minnesota, USA. The response rate was 81.5%. Rates of UWCBs were compared across the spectrum of prevalence of trying to lose weight and friends’ involvement with dieting, using χ2 analysis and multivariate logistic regression, controlling for demographic factors and clustering by school.

Girls with higher body mass index (BMI) were more likely to engage in UWCBs than those of lower BMI. Multivariate models indicated that friends’ dieting behavior was significantly associated with UWCBs for average weight girls and moderately overweight girls. The school-wide prevalence of trying to lose weight was significantly, albeit modestly, related to UWCBs for average weight girls, and marginally associated for modestly overweight girls, even after controlling for friends’ dieting behaviors. The social influences examined here were not associated with UWCBs among underweight (less than 15th percentile) or overweight (more than 95th percentile) girls. Findings suggest that social norms, particularly from within one's peer group, but also at the larger school level may influence UWCBs, particularly for average weight girls.

This research suggests the possible influential role of social norms above and beyond the role of friends’ attitudes and behaviors. Future research should build on these findings by examining multiple measures of social norms and friends’ dieting, as well as additional social influences which might play a part in UWCBs, such as pressure from family members or media. Longitudinal studies are also warranted, to determine the causal nature of these associations.

Austin (2001) applies Rose's (1992) prevention paradigm to UWCBs by pointing out that the largest number of cases of unhealthy weight control arise from dieting among normal weight girls (those in the middle of the BMI curve), rather than among overweight girls (those typically considered at high risk). Thus, a reduction in the prevalence (a “shift in the curve”, to use Rose's language) of dieting behavior among normal weight girls would result in a reduction in cases of UWCBs.

In keeping with this framework, our findings suggest that interventions aimed at changing school norms of dieting may have the potential for influencing UWCBs among individual girls. School-based programs have the advantage of involving a large number of young people, which is an essential step toward changing social norms in this population. Although healthy weight gain prevention methods are appropriate for weight management, school administrators, teachers, school nurses, and other personnel should work toward a decreased emphasis on the “thin-ideal” and dieting as a normative behavior among girls of a normal, healthy weight. Educational programs which teach skills to critically evaluate cultural messages about femininity and beauty may be a useful in reducing body dissatisfaction, dieting, and UWCBs. Such programs should also include an emphasis on healthy eating and physical activity for overall health. As dieting behavior and body dissatisfaction have been noted in girls in elementary school and preschool, initiating such programs at a young age may be advisable in order to prevent the development of UWCBs in adolescence.

The development of curricula, policies, and programs aimed at shifting the social norm away from unnecessary dieting is warranted. Further research is needed to test these components in a variety of school settings in order to identify successful strategies for changing social norms in a school context.