Psychoneurological Links Contributing to Body Mass Index and Eating Disorder Severity

Background-objectives: Multiple dynamic interacting factors contribute to the presence and progression of eating disorders (ED). Empirical research has provided mixed findings regarding the mechanisms explaining the contribution of body mass index (BMI) to the diverse ED endophenotypes. The present study aims to evaluate the underlying processes (direct and indirect effects) contributing to BMI and ED severity, considering the contribution of multiple neuropsychological constructs. Method: Path analysis, implemented through structural equation models (SEM), was applied to a sample of N = 193 ED patients, men and women, aged 17 to 50 years old, and diagnosed with bulimia nervosa, night eating syndrome, binge eating disorder, and other specified feeding. Results: BMI was directly associated with ED severity level. The ED symptom level was also a mediational link into the relationship between BMI with emotion regulation strategies, decision-making capacity, stress levels, and impulsiveness. Multigroup SEM revealed invariance of the structural coefficients by sex, but differences according to the ED subtype. Conclusions: This study provides new empirical evidence on predictors of ED severity, focusing on the role of impaired decision-making and BMI. Our results could contribute to new intervention plans with techniques specifically aimed at improving emotional regulation capacity, decreasing impulsivity levels, and improving reasoning skills. Nutrition education plans may also play a key role for preventing the onset and progression of ED, helping patients understand how food affects their physical and emotional health and how to manage anxiety and fears related to food.