Eating behaviour in treatment-seeking obese subjects - Influence of sex and BMI classes

Obese subjects frequently show an adversely altered eating behaviour. However, little is known on differences in eating behaviour across different degree of obesity. We analysed data on the three factor eating questionnaire assessing cognitive restraint, disinhibition, and hunger that were filled in by 664 obese patients (469 women) who seeked treatment in our Interdisciplinary Obesity Center. Patients were divided in five BMI classes (30 - <35 kg/m(2), 35 - <40 kg/m(2), 40 - <50 kg/m(2), and >50 kg/m(2)). Multivariate regression analyses revealed that sex was significantly related to all three eating behaviour traits (all P < 0.042) but no significant relation to BMI (as a continuous variable) was observed. Women in comparison to men showed significantly higher cognitive restraint (9.7 ± 4.3 vs. 7.7 ± 4.4; P < 0.001) and disinhibition (9.0 ± 3.5 vs. 7.7 ± 3.5; P < 0.001) scores and also showed higher hunger scores (6.9 ± 3.7 vs. 6.3 ± 3.5; P = 0.042). Analyses on different BMI classes revealed that cognitive restraint decreased (P = 0.016) while disinhibition (P = 0.010) and hunger (P = 0.044) increased independently of sex with increasing BMI classes. However, above the obesity grade I class (i.e. BMI 30 - < 35 kg/m(2)) there were no differences in eating behaviour variables between the remaining BMI classes. Data indicate profound differences in eating behaviour between women and men that persist across a wide range of obesity. Furthermore, data suggest that while grade I obese patients show higher cognitive restraint and less disinhibition and hunger scores than more severe obese patients these dimensions of eating behaviour do not systematically vary across higher BMI classes.