Diet Stacking - An Expanding Challenge for Gastroenterologists and Dietitians in Managing Chronic Gastrointestinal Disorders.

Dietary therapy has an established role in managing gastrointestinal disorders, as a short-term induction therapy (e.g., exclusive enteral nutrition for Crohn's disease), a long-term monotherapy (e.g., gluten-free diet for coeliac disease and a personalized FODMAP diet) or adjunct therapy (e.g., Mediterranean diet). As use of dietary therapies rises, it is becoming increasingly common for gastroenterologists and dietitians to encounter patients who are simultaneously following two or more dietary therapies to achieve optimal symptom control, to manage multiple concurrent medical issues, or for social or religious reasons. This practice is termed 'diet stacking'. The aim of this review is to clarify the principles behind the safe and effective combination of dietary interventions with specific attention to potential risks, mitigation of risk and practical application. For gastroenterologists, awareness of current dietary practices of their patients prior to advising dietary therapy is warranted and, in those who are diet stacking, risk assessment is essential. Validated screening tools to evaluate risks, particularly of disordered eating, are limited. The management of those who currently or are at risk of diet stacking is best directed toward gastrointestinal dietitians who offer time, appropriate skills for assessment, and the delivery of pragmatic patient education to safely implement appropriate dietary interventions, and assess for the need for engaging psychological primary management or co-management. In conclusion, diet stacking is common, and requires awareness and often multi-disciplinary management to ensure it is implemented safely.