Body Image Distortion in Relationship to Onset of Three Types of Weight Control Behaviors Among Adolescent Girls in the U.S

Purpose: To longitudinally examine body image distortion as a risk factor for the onset of three types of weight control behavior among adolescent girls: dieting, extreme methods, and exercise. Weight-control behaviors among adolescents are not benign. Recent studies confirm that dieting based on rigorous calorie restriction among children and adolescents is iatrogenic, and associated with subsequent weight gain, weight cycling, appetite dysregulation, depression, and adulthood obesity. Moreover, extreme and unsafe weight control behaviors such as vomiting, laxatives and diet pills have been strongly associated with eating disorders. In contrast, moderate exercise has been shown to have salutary effects on mood and self-concept. To date, body image dissatisfaction has received much theoretical and empirical attention as a precursor to weight-related health behaviors, but its near ubiquity among adolescent girls (60-80%) limits its usefulness in research. A more discriminating indicator of problematic body image may be the presence of body image distortion (BID), i.e., the observed cognitive discrepancy between a girl's perception of her weight status and her BMI-for-age weight status. Theoretically, cognitive distortion about one's appearance represents a more entrenched negative body image than mere dissatisfaction; however, whether or not BID increases a girl's risk for unhealthy weight control behavior has not been established, and is thus the empirical question addressed by this study.

Methods: Two waves of data on girls (n=2370) were extracted from the National Longitudinal Study of Adolescent Health, a nationally representative study of high school aged adolescents. Logistic regression analyses compared girls with and without BID on newly reported use of three types of weight control behaviors in the subsequent year, controlling for baseline weight control activity, age, SES, and race/ethnicity. Extreme weight control refers to the use of diet pills, laxatives, or induced vomiting within the previous 7 days. Dieting and exercising to control weight in the previous 7 days were also based on self-report. A longitudinal design was used to establish temporal order and assess onset of new behavior.

Results: Girls with BID had 6.3 greater odds of beginning extreme weight control behavior (e.g., vomiting, laxatives, diet pills) within one year than girls without BID (OR = 6.28, CI= 2.74, 14.38); and 2.6 greater odds of beginning to diet to control weight (OR = 2.64, CI= 1.97, 3.53) than their non-BID counterparts. However, girls with BID showed no change in odds of beginning to exercise for weight control than their non-BID counterparts.

Conclusions: Data show that BID significantly increases girls' risk for engaging in dieting and extreme weight control behaviors, but is unrelated to exercising to control weight. These findings lend support for including BID as a salient feature of prevention and intervention programs and as a discriminating factor in risk/resilience studies related to adolescent weight management and disordered eating. Findings also suggest that a brief BID screening tool for use with adolescents by physicians in primary care or by social workers in schools and mental health settings could help identify girls at risk for unsafe weight control behavior.