Orthorexia Nervosa Inventory (ONI): development and validation of a new measure of orthorexic symptomatology

Purpose: To overcome the problems associated with existing measures of orthorexia, we assessed the reliability and validity of a new measure: the Orthorexia Nervosa Inventory (ONI). Method: An online survey was completed by 847 people recruited from undergraduate nutrition and psychology courses and from advertisements in Facebook and Instagram targeting both healthy eaters (with keywords such as “clean eating” and “healthy eating”) and normal eaters (with keywords such as “delicious food” and “desserts”). Results: Exploratory factor analysis revealed three factors with 9 items assessing behaviors and preoccupation with healthy eating, 10 items assessing physical and psychosocial impairments, and 5 items assessing emotional distress. With this sample, all scales demonstrated good internal consistency (Cronbach’s α= 0.88–0.90) and 2-week test–retest reliability (r= 0.86– 0.87). Consistent with past research, ONI scores were significantly greater among vegetarians and vegans, and among those with higher levels of disordered eating, general obsessive–compulsive tendencies, and compulsive exercise. Additionally, whereas ONI scores did not significantly differ between men and women, the scores were negatively correlated with body mass index. Conclusion: The ONI is the first orthorexia measure to include items assessing physical impairments that researchers and clinicians agree comprise a key component of the disorder. Additionally, at least for the current sample, the ONI is a reliable measure with expected correlations based on the past research. Level of evidence: Level V, descriptive cross-sectional study.