Review article: exclude or expose? The paradox of conceptually opposite treatments for irritable bowel syndrome

Aliment Pharmacol Ther. 2022 Aug;56(4):592-605. doi: 10.1111/apt.17111. Epub 2022 Jul 1.


Background: Irritable bowel syndrome (IBS) is a heterogeneous disorder of gut-brain interaction (DGBI) maintained by interacting biological, psychological, and social processes. Interestingly, there are two contrasting yet evidence-based treatment approaches for reducing IBS symptoms: exclusion diets such as those low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and exposure-based cognitive-behavioural therapy (CBT). Exclusion diets recommend patients avoid foods thought to be symptom-inducing, whereas exposure-based CBT encourages patients to expose themselves to foods.

Aims: To address the paradox of conceptually opposite exclusion diets and exposure-based CBT for IBS.

Methods: In this conceptual review, we describe the rationale, practical implementation, evidence base and strengths and weaknesses of each treatment. We conducted up-to-date literature search concerning the low FODMAP diet and CBT, and performed a secondary analysis of a previously conducted trial to illustrate a key point in our review.

Results: The low FODMAP diet has demonstrated efficacy, but problems with adherence, nutritional compromise, and heightened gastrointestinal-specific anxiety raise caution. Exposure-based CBT has demonstrated efficacy with substantial evidence for gastrointestinal-specific anxiety as a key mechanism of action. Mediation analysis also showed that increased FODMAP intake mediated decreased symptom severity in exposure-based CBT. However, there is minimal evidence supporting which treatment "works best for whom" and how these approaches could be best integrated.

Conclusions: Even though exclusion diets and exposure-based CBT are conceptually opposite, they each have proven efficacy. Clinicians should familiarise themselves with both treatments. Further research is needed on predictors, mechanisms and moderators of treatment outcomes.

Keywords: cognitive-behavioural therapy; exclusion diets; exposure-based therapy; irritable bowel syndrome; low FODMAP diet.

Publication types

  • Review
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Clinical Trials as Topic
  • Cognitive Behavioral Therapy*
  • Diet, Carbohydrate-Restricted*
  • Humans
  • Irritable Bowel Syndrome* / therapy
  • Treatment Outcome