Restrict for Health or for Thinness? Liking but Not Approach Bias Differentiates Orthorexic Eating Behavior From Anorexia Nervosa in Responses to High-Caloric Healthy vs. High-Caloric Unhealthy Foods.

OBJECTIVE: Individuals with high levels of orthorexic eating behavior (OEB) show a (pathological) fixation on healthy eating. Shared characteristics of OEB with individuals with anorexia nervosa (AN) raised debate over whether orthorexia nervosa constitutes a distinct disorder. Distinctions may lie in preference for and approach behavior toward foods differing in calorie content and healthiness. We expected reduced liking and weaker approach biases in AN and OEB compared with controls; specifically for high-caloric foods in AN and for unhealthy foods in OEB.

METHOD: Thirty-five self-reported AN, forty non-AN individuals who scored > 30 on the Düsseldorf Orthorexia Scale (OEB), and 101 individuals with no eating disorder history (controls) completed liking ratings and an Approach-Avoidance Task with food stimuli varying in calorie content (high vs. low) and, for high-calorie items, healthiness (healthy vs. unhealthy).

RESULTS: Compared to controls, AN reported lower liking for all high-caloric foods, while OEB reported lower liking only for high-caloric, unhealthy foods. Accordingly, OEB also liked high-caloric healthy foods more than AN. AN showed weaker approach bias than controls (mainly driven by high-caloric unhealthy foods). OEB descriptively lay between both other groups, with no significant differences in approach bias to either.

CONCLUSION: Explicit liking ratings distinguished AN from OEB aligning with their respective motivation to reduce high-caloric versus unhealthy food intake. Reduced approach bias was specific to AN, possibly reflecting rapid engagement of approach-avoidance responses to easy-to-categorize high-caloric unhealthy foods. Contrary, health-focused processing in OEB may require slower deliberations that are not captured by approach-avoidance tasks.