Abstract
Orthorexia nervosa (ON), described as a pathological obsession with healthy eating (Dunn & Bratman, 2016), still presents no consensual definition, notably in regard to body image disturbance. This study applied the psychophysical method of Reverse Correlation (Mangini & Biederman, 2004) to verify if ON symptomatology, measured with the Eating Habit Questionnaire (Gleaves et al., 2013), is associated with body image dissatisfaction and/or misperception. Validity of Reverse Correlation for body image measurements was also verified by comparing it to a self-report questionnaire (Cash, 2000). Reverse Correlation allowed to reveal participants mental representation (MR) of their current (task 1) and ideal (task 2) body images. Every trial (500/task), participants (n=68) viewed two stimuli depicting their own body overlaid in white sinusoidal noise. They had to decide which one was the most similar to their current (task 1) or ideal (task 2) body. Classification images representing MR of their current and ideal body were calculated by averaging all noise patches that were added to selected stimuli. Body misperception corresponded to the difference between real body and MR of current body; and body dissatisfaction to difference between MRs of current and ideal body. To measure these differences, independent groups (n=64) compared images on their level of fat (group 1), and muscularity (group 2). Body misperception and dissatisfaction scores obtained with Reverse Correlation correlated with the self-report measure (r=.242 to .535, p=.000 to .054), supporting its use to assess body image disturbance. ON correlated with body fat dissatisfaction with whole body, arms/shoulders, chest/breast, abdomen, hips, thighs, and muscularity dissatisfaction for chest/breast and hips (r=.238 to .314, p=.009 to .051). ON also correlated with muscularity misperceptions for arms/shoulders (r=.236, p=.053) and abdomen (r=.238, p=.051). ON was not related to body fat misperceptions (all p’s>.148). These results suggest that body image disturbance is part of orthorexia features.