Eating Disorders in the Context of Gastrointestinal Diseases-A Narrative Review.

Background/Objectives: The clinical overlap between gastrointestinal (GI) conditions and psychiatric disorders represents a challenge in clinical practice. Eating disorders (EDs), including anorexia nervosa, bulimia nervosa, binge eating disorder (BED), and avoidant/restrictive food intake disorder (ARFID), may co-occur with gastrointestinal (GI) diseases and complicate their management. Orthorexia nervosa is a proposed and emerging construct characterized by pathological preoccupation with healthy eating and rigid dietary practices. This narrative review aims to summarize current evidence regarding eating disorder symptomatology, ARFID screening and diagnosis, orthorexic symptomatology, pathophysiological mechanisms, and diagnostic challenges across gastrointestinal diseases, with particular attention to inflammatory bowel disease (IBD), disorders of gut-brain interaction (DGBIs), celiac disease, eosinophilic esophagitis, upper gastrointestinal motility disorders, and the potential role of the gut microbiota. Methods: The review was structured in accordance with the SANRA guidelines. A structured literature search was conducted primarily in PubMed, with Scopus and Google Scholar used as supplementary sources for identifying additional relevant publications through citation tracking and examination of reference networks, for articles published from 2011 through early 2026. Results: The available literature indicates an association between GI disorders and disordered eating, with potentially bidirectional relationships involving symptom burden, dietary restriction, psychological factors, and gut-brain signaling. Chronic GI symptoms often necessitate dietary modifications, which can inadvertently trigger or mask pathological restrictive eating behaviors. Diagnosing ARFID and orthorexia in these cohorts is particularly challenging due to overlapping somatic symptoms. Primary EDs are also associated with gastrointestinal symptoms and alterations in the gut microbiome; however, human evidence remains predominantly observational, and the temporal and causal relationships between dysbiosis, nutritional restriction, inflammation, and gastrointestinal dysfunction remain uncertain. Conclusions: The convergence of EDs and GI conditions requires heightened clinical vigilance. Distinguishing between necessary, symptom-driven dietary restrictions and pathological eating behaviors is crucial. Implementing an integrated, multidisciplinary care model-involving gastroenterologists, psychiatrists, and dietitians-is essential to improve diagnostic accuracy and patient outcomes.