Optimizing the empirical assessment of orthorexia nervosa through EHQ and clarifying its relationship with BMI

Orthorexia nervosa (ON) is described as an obsession for healthy eating with potentially debilitating consequences but little of its psychopathology is empirically supported. Using suitable validation methodologies, we wanted to optimize the empirical assessment of ON symptoms and investigate their unclear relationship with BMI. Our objective was, therefore, twofold: (1) Validation of a robust measurement model of ON dimensions using the Eating Habits Questionnaire (EHQ); (2) Validation of a structural model describing a mechanism of relationships between ON dimensions and BMI.

A self-report questionnaire assessing BMI and ON through a French translation of the 21-item EHQ was administered to a large sample of French adults (N = 2065). We used Exploratory and Confirmatory Factor Analysis for objective no. 1 and Structural Equation Modeling for objective no. 2.

We validated a well-fitted (TLI = 0.98; RMSEA = 0.04) and conceptually consistent measurement model with 16 items for three ON dimensions: Rigid Eating Behavior (REB), Positive Feeling of Control (PFC) and Problems of Attention Control and Social Relationships (PACSR). We also validated a structural model (TLI = 0.96; RMSEA = 0.05) showing that: 1. REB strongly impacts both PFC and PACSR; 2. REB has a significant negative impact on BMI and BMI has a significant positive effect on PACSR but effect sizes are very small and globally ON dimensions are only marginally related to BMI.

Our study achieved an improved assessment method of ON, a clarification of its links with BMI and implications for the descriptive psychopathology of ON.

V, Descriptive cross-sectional study.