Orthorexia Nervosa (ON) has been a research focus in recent years. Despite the lack of consensus on its definition and classification as a psychiatric disorder, research has shown that ON is linked to certain behaviours (orthorexic behaviours, e.g.: obsessive thinking and compulsive behavior, guilt and self-punishment, restriction), associated with disordered eating. However, very little is known about this relationship. The aim of this study was to explore the eating-related processes inherent to the relationship between orthorexic behaviours and disordered eating, and understand if it is through the adoption of a more inflexible and less intuitive eating approach, that an interest in healthy eating develops into a pathological one, while controlling the effect of age and BMI. Additionally, this relationship was explored for two different groups: Omnivores and Non-omnivores.