The mediating role of perceived body weight, fat, and muscularity in the relationship between weight status and psychological health

Background: Past studies have primarily focused on the impact of body weight perception on psychological health. However, other components (e.g., perceived body fat and muscularity) may also play a role. This study aimed to examine the association between weight status (i.e., normal weight and obesity/overweight) and psychological health, and how different components of body perception mediate the association.Methods: From February to June 2022, 621 undergraduates completed an online cross sectional survey, which included questions about height, weight, psychological health (i.e., well-being, quality of life, depression, anxiety, and stress), and body perception. Participants with a body mass index (BMI) between 18.5 kg/m2 and 25 kg/m2 were classified as normal weight, while those over 25 kg/m2 were classified as individuals with obesity/overweight. Path analysis tested the association between weight status and psychological health and the mediating role of perceived body weight, fat, and muscularity.Results: Obesity/overweight was associated with lower well-being (β = 0.128, p=0.002) and physical health-related quality of life (β = 0.089, p=0.024), and higher depression (β =-0.133, p=0.002) and stress (β =-0.104, p=0.013). These associations were fully mediated by perceived body fat, with estimates ranging from-0.122 to 0.112. Perceived body weight and perceived muscularity did not significantly mediate these associations.Conclusion: Perceived body fat was the only component of body perception that explained the association between weight status and psychological health. This finding suggests that research on psychological health in individuals with obesity or overweight needs to extend beyond mere perceived body weight and incorporate different components of body perception. Furthermore, interventions aimed at improving psychological health in individuals with obesity or overweight need to consider the potential effect of perceived body fat.