Exclusion diets to diagnose food intolerance

Exclusion diets involve excluding food groups or components of food groups from the diet to help identify the food or group of foods triggering symptoms. These foods can then be avoided to manage symptoms.

Exclusion diets should only be implemented for the shortest time possible to assess symptom improvement. In children, an exclusion diet should only be initiated and managed by a paediatric gastroenterologist. In adults, an exclusion diet should be undertaken with guidance from a medical practitioner and a specialist accredited practising dietitian (APD). If symptoms do not improve after 4 weeks, food intolerance is unlikely and alternative causes of symptoms should be considered. To avoid over-restriction when planning ongoing therapy, gradually reintroduce foods to identify triggers.

Exclusion diets may be difficult to follow, and there is a risk that the diet may not be nutritionally adequate or may be associated with unhealthy eating habits. A specialist APD can suggest alternative foods to ensure nutritional adequacy, and closely monitor the patient’s symptomatic response to foods.

Exclusion diets should be avoided in patients with malnutrition and those with an existing or suspected eating disorder (see the Psychotropic guidelines)—alternative management strategies should be usedHarer, 2021Mari, 2019.