Orthorexia nervosa and dieting in a non-clinical sample: a prospective study

PURPOSE: Orthorexia Nervosa (ON) is characterised by excessive attention to a dietary regimen perceived as healthy. A critical factor in the distinction between ON and other eating disorders (EDs) is the dichotomy of quality-versus-quantity of food intake. We investigated whether specific types of diet or dieting frequency are associated with orthorexic features, explored the overlap between ON and EDs symptoms, and examined which constructs are predictive of ON after 6 months. METHODS: A total of 1075 students (75.1% female, mean age 20.9) completed a set of questionnaires assessing Orthorexia, Eating Disorders, Obsessions and Compulsions, Anxiety and Depression; 358 individuals (79.9 female, mean age 20.9) agreed to participate in the study and completed the same questionnaires after 6 months. Different regression models were defined to investigate our hypothesis. RESULTS: Findings suggest that ON is associated with the number and type of diets followed over a lifetime. Moreover, participants with EDs, body dissatisfaction, or a dysfunctional idea of thinness are more likely to report a greater degree of ON features. After 6 months, the best predictors of ON characteristics are the same ON characteristics assessed at the first administration, with a significant role in the ideal of thinness. CONCLUSIONS: ON is more frequent in individuals with a previous diagnosis of EDs and in individuals who followed a restrictive diet or a vegan/vegetarian one; the number of lifetime diets, beliefs, and behaviors related to the ideals of thinness or body dissatisfaction is common features of ON. Moreover, considering that having ON features in the past is the best ON predictor in the present, we can presume that ON is a construct stable over time. LEVEL OF EVIDENCE: Level IV: Evidence obtained from multiple time series analysis such as case studies. (NB: Dramatic results in uncontrolled trials might also be regarded as this type of evidence). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40519-021-01353-8.