Eating Habits Questionnaire-21

Orthorexia was assessed using the Italian version of the 21-item Eating Habits Questionnaire (EHQ-21) [48, 49]. This self-report measure explores (a) beliefs related to healthy eating (via the “Knowledge” subscale; example item: “My eating habits are superior to others”), (b) feelings associated with healthy eating (via the “Feelings” subscale; example item: “I feel in control when I eat healthily”), and (c) problems related to these behaviors (via the “Problems” subscale; example item: “I turn down social offers that involve eating unhealthy food”). According to Zickgraf et al. [50], specifically the “Problems” subscale is particularly valuable in discriminating the orthorexic condition from normal healthy-eating behaviors. All items are rated on a four-point Likert scale, ranging from 1 (false, not at all true) to 4 (very true). The original version of EHQ-21 has good internal consistency and test–retest reliability, as well as adequate convergent, discriminant and criterion-related validity [48]. In the present sample, Cronbach’s alpha values were 0.80, 0.63, and 0.83 for the Knowledge, Feelings, and Problems subscales, respectively.

Based on the EHQ-21 scores, participants were grouped into the ON symptoms, normal-eating control and healthy-eating control groups by applying criteria established by Oberle and colleagues [18].