Comparing a low-FODMAP diet program versus exposure-based cognitive behavioral therapy for people with IBS
Official title: Exclude or Expose in Irritable Bowel Syndrome: What Works for Whom, and How? A Randomized Controlled Trial of Internet-Delivered FODMAP Diet Versus Exposure-Based Cognitive Behavioral Therapy
Run by University of Melbourne · NCT06940596 · Data updated 2026-11-12
This project will test whether an online low-FODMAP diet program or an online exposure-based cognitive behavioral therapy better reduces IBS symptoms in adults.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years and up |
| Sex | All |
| Enrollment | 235 (estimated) |
| Sponsor | University of Melbourne Academic / other |
| Locations | 1 site (Melbourne, Victoria) |
| Status | Recruiting |
| Started | May 22, 2025 |
| Main results expected | October 2027 |
| Study ends | April 2028 |
| Registry record updated | May 6, 2026 |
| Trial ID | NCT06940596 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults (18+) living in Australia or the United States with a clinical IBS diagnosis who meet Rome IV criteria, have an IBS-SSS score above 175, a BMI between 18.5 and 34.9 kg/m2, internet access, and sufficient English and computer skills are ideal candidates.
✕Probably not a fit
People with other organic GI diseases (for example celiac disease or inflammatory bowel disease), a history of major gastrointestinal surgery or cancer, those outside the BMI range, or those without internet/English/computer access are unlikely to be eligible or to benefit from these online programs.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This is a randomized controlled trial that assigns adults with Rome IV–defined IBS to one of two online programs: a structured low-FODMAP diet program (with restriction, reintroduction, and personalization phases) or an exposure-based cognitive behavioral therapy (E-CBT) program focusing on changing symptom-related behaviors. Outcomes will include changes in gastrointestinal symptoms during treatment and analyses of moderators (which patients respond best to which treatment) and mediators (how each treatment produces change). Both interventions are delivered remotely and require participants to complete self-monitoring and program exercises over multiple phases. The investigators aim to identify who benefits most from dietary versus behavioral approaches to help personalize IBS care.
Why it matters
Potential benefit: If successful, the findings could help match people with IBS to the dietary or behavioral treatment most likely to reduce their symptoms.
How similar studies have gone: Prior randomized trials have shown that low-FODMAP diets and cognitive behavioral therapies can improve IBS symptoms, though direct head-to-head comparisons and detailed moderator/mediator analyses are less common.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: Each participant must meet all of the following criteria to be enrolled in this trial: * Living in Australia or the United States * Aged 18 years or older * Body Mass Index (BMI) \[Equation\]18.5kg/m2 and \[Equation\] 34.9kg/m2 * Diagnosed with IBS by a General Practitioner, Family Physician, or Gastroenterologist, or Advanced Specialist Dietitian * Currently fulfill Rome IV criteria for IBS * Symptomatic at the time of recruitment (IBS-SSS \> 175) * Access to a computer and internet * Sufficient English language and computer skills to complete a text-based online treatment * Willing to make dietary or behavioral changes in line with the allocated treatment program * Ability to provide informed consent Exclusion Criteria:Patients meeting any of the following criteria will be excluded from the trial: * Presence or known history of other GI disease (e.g. coeliac disease, Inflammatory Bowel Disease) or history of gastrointestinal cancer * History of major gastrointestinal surgery (not appendectomy, cholecystectomy or hemorrhoidectomy) * Individuals who report alarm symptoms (e.g., blood in stool, recent unexplained/unintentional weight loss \>5% body weight, a recent change in bowel habits if \>50 years, family history of gastrointestinal cancer or gastrointestinal diseases, large volumes of diarrhea occurring at night, fever associated with gut symptoms, recurrent vomiting, persistent unexplained iron deficiency) will be excluded if appropriate medical investigations have not been conducted, unless written medical approval is provided from a general practitioner, family physical, or gastroenterologist. * Diagnosis of major disease that could explain current gastrointestinal symptoms such as severe diabetic, cardiac, liver, neurological, neuropathy disease * History or current diagnosis of psychotic disorder or bipolar disorder * Current diagnosis of substance abuse disorder or major depressive disorder or active suicidal ideation * History or current diagnosis of an eating disorder * Current enteral/parenteral feeding or use of supplemental feeds (e.g. Ensure) * Pregnant or lactating or planning to become pregnant during the 12-week intervention period * Commenced or change in dose of antibiotics and medications that potentially affect the gastrointestinal transit (e.g. anti-diarrheals and laxatives) in the 3 months preceding study commencement. * Commenced taking or changed dose of probiotics, prebiotics, fibre supplements and digestive enzymes in the 3 months preceding study commencement * Commenced or change dose in psychotropic medication in the 3 months preceding study commencement * Are currently undertaking behavioral therapy for IBS (including cognitive behavioral therapy, CBT), or have undertaken clinician-delivered behavioral therapy for the treatment of IBS * Are currently undertaking or have undertaken a dietitian-prescribed and delivered restrictive diet for IBS (e.g., FODMAP diet).
Where it's running
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University of Melbourne
Melbourne, Victoria, Australia Recruiting
Study contacts
- Principal investigator: Associate Professor Jessica Biesiekierski — University of Melbourne
- Study coordinator: Jessica Biesiekierski, A/Prof
- Email: jessica.biesiekierski@unimelb.edu.au
- Phone: +61 499 272 673
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.