Beyond the Myth of Slimming: The Impact of Social Norms on Positive Body Image and Caloric Intake among Young Adults

How does the "thin ideal" social norm, which equates thinness with beauty, affect young people's body image and calorie intake? In one questionnaire survey and three intervention experiments (N = 612), we propose that people’s beliefs about the “thin ideal” social norm shape their positive body image and caloric intake. Specifically, we find that a stronger belief in the "thin ideal" was associated with a lower level of positive body image, with BMI self-discrepancy mediating this effect (Study 1). To address these misperceptions about the “thin ideal” social norm, we further evaluated social norm interventions, demonstrating their positive impact on positive body image and calorie intake. Since the role of injunctive social norm interventions was limited (Study 2), we adopted the more descriptive interventions and those incorporating role model factors (Study 3), with the latter showing longer-lasting effects (Study 4). These findings enhance understanding of the influence of the "thin ideal" social norm and suggest practical interventions for improving positive body image and health behaviors.