The relationship between fat mass, eating behaviour and obesity-related psychological traits in overweight and obese individuals

Behavioural and psychological factors related to eating have been associated with obesity, although their relationship to anthropometric measures, more specifically fat mass, has not been fully examined. This study examined the relationship between fat mass (n = 98; 75M, 23 F) and behavioural measures of eating and obesity related psychological traits (n = 337; 226M, 111 F) in overweight and obese individuals (Mean BMI 30.5 ± 4.0; BMI range 25–46 kg/m2). Two sets of principal component analyses (PCA) were performed: one on validated questionnaires of eating behaviour and psychological traits and a second on fat mass and body weight related anthropometric measures (BMI, weight) and the aforementioned questionnaire measures. From the initial PCA (n = 337), the primary principal component, P1 (R2 value of 0.33), represented a latent variable associated with overeating or binge eating behaviour. In a second PCA (questionnaire measures augmented by anthropometric variables, n = 98), a single component was identified, P1+ (R2 of 0.28), similar to that identified as P1 in the previous analysis and this component was highly correlated with fat mass (ρ = 0.68). These findings suggest that levels of body fat and eating behaviour (namely, binging or overeating) are strongly related and, at least in a subgroup of individuals, obesity may be driven by behavioural factors associated with eating in combination with pre-existing environmental and genetic factors.