The facets of conscientiousness and body mass index: Potential mediation by eating factors

High Conscientiousness (C) is linked to lower body mass index (BMI); however, the facets of C have not yet been analyzed in relation to BMI while adjusting for other personality domains or one another. The objectives of this study were to examine: 1) the BMI-C relationship within the broader context of the Five Factor Model (FFM) domains, 2) unique BMI-C relationships at both the C domain and facet levels, and 3) the role of eating factors as potential mediators of observed relationships. The sample was 542 young adults (20.2 ± 3.6 years) from a Midwestern university. Personality was assessed using the IPIP-NEO-120. BMI was calculated from self-reported height and weight. Eating factors were measured with the Three-Factor Eating Questionnaire. Linear regressions were used to investigate associations between personality domains/facets and BMI adjusting for covariates. The C domain score was not associated with BMI (β = −0.03, p = .187). Facet-level analysis showed that the high orderliness C facet was uniquely associated with lower BMI (β = −0.22, p = .005). Indirect effects analysis revealed that disinhibited eating potentially mediates the orderliness-BMI relationship (β = 0.56, SE = 0.07, CI[0.43, 0.70], p < .001). If corroborated with prospective studies, low orderliness may be a key risk factor for problematic weight regulation and a valuable treatment target.