Evidence and Implications of Weight Clustering Among Adolescents

Both obesity and eating disorders (ED) are increasingly conceptualized from an ecological model of health, which emphasizes the importance of individual and contextual variables. The peer context is particularly important for understanding adolescents’ weight related attitudes and behaviors; however, specific peer processes that impact obesity and EDs are unclear. Because social comparison is common during adolescence, how teens view their body in comparison to the body size of their close friends may be influential. The purpose of this study is to examine how adolescents’ perceptions of their friends’ body sizes relate to their weight-related cognitions, behaviors, and mental health symptoms, and to identify peer processes that mediate these associations. Adolescents provided self-report on weight related cognitions and behaviors including: defining self as overweight, dieting, exercise, body satisfaction, ED symptoms, and depressive symptoms. Using a figure rating scale, participants also reported on their figure size and the sizes of their four closest friends. Analyses indicated that adolescents who rated themselves as having a larger figure also had friends who they perceived as relatively large (i.e., weight clustering). For girls but not boys, the perceived size of friends (e.g., rating of largest and thinnest friend) predicted whether or not the adolescent identified as overweight, felt body dissatisfaction, engaged in recent dieting, and endorsed ED symptoms, beyond the effect of BMI and self figure rating. There was some indication that peer group preoccupation with weight may mediate these effects, although in general there was little support for the potential mediating mechanisms tested. Results provide additional evidence of weight clustering among peer groups, and indicate this clustering may have an impact on how adolescents view their weight. Consequently, prevention programs that address negative aspects of social comparison or are delivered in peer groups may be especially important