Indirect effects of trait impulsivity on body mass

Trait impulsivity has been suggested as a risk factor for weight gain. However, it is implausible that a construct that does not cover energy intake or expenditure affects fat mass directly. Instead, it is likely that eating-related variables mediate the effect of impulsivity on body mass. In the current study, a serial mediation model tested two eating-related variables (trait food craving and perceived self-regulatory success in weight regulation) as mediators of the relationship between trait impulsivity and body mass. Participants (n=432, 88% female, 79% students) completed the Barratt Impulsiveness Scale - short form, the Food Cravings Questionnaire-Trait-reduced, and the Perceived Self-Regulatory Success in Dieting Scale (PSRS), in addition to providing sociodemographic and anthropometric data. Trait impulsivity did not correlate with body mass index (BMI), but was indirectly related to BMI via food cravings and PSRS scores. Specifically, higher impulsivity predicted more frequent food cravings, which in turn predicted lower perceived self-regulatory success in eating and weight regulation, which in turn predicted higher BMI. Findings suggest possible mechanisms that mediate the association between impulsivity and BMI. Importantly, they show that impulsivity can indirectly affect BMI via eating-related variables, even in the absence of a total effect. Longitudinal studies are needed that support these assumed causal directions.