The long-term effect and adherence of a low fermentable oligosaccharides disaccharides monosaccharides and polyols (FODMAP) diet in patients with irritable bowel syndrome

J Hum Nutr Diet. 2020 Apr;33(2):159-169. doi: 10.1111/jhn.12706. Epub 2019 Oct 22.


Background: Short-term trials with a low-FODMAP (fermentable oligosaccharides disaccharides monosaccharides and polyols) diet (LFD) show promising results in the symptomatic management of irritable bowel syndrome (IBS). The present study investigated the long-term adherence to an LFD diet, factors associated with adherence, and associations between LFD and quality of life (QOL), IBS symptoms and disease course on a long-term basis.

Methods: A retrospective cross-sectional study was conducted. Two hundred and thirty-four patients were enrolled from Ghent University hospital. Health-related QOL, long-term adherence to the LFD, disease course and IBS symptoms were assessed using a validated and self-developed questionnaire.

Results: Ninety (38.5%) patients completed the questionnaires. The median time span between the first dietary consultation and completion of the questionnaires was 99.5 weeks (approaching 2 years). The predominant disease course was mild IBS with an indolent course (43.0%). Eighty percent reported still following a diet in which certain FODMAP-rich food types are avoided. Eighty patients (88.9%) were satisfied that they follow or had followed the diet. The IBS-QOL did not differ between patients following the diet strictly and patients deviating from the diet (P = 0.669). Patients still following the LFD experienced less severe abdominal pain than patients who stopped following the diet (P = 0.044).

Conclusions: The long-term adherence and satisfaction with the LFD is high in patients with IBS. Nevertheless, patients indicated that it was difficult to follow the LFD in daily life. Practical issues, social factors and the absence of symptoms were indicated as the main reasons for a drop in adherence.

Keywords: adherence; irritable bowel syndrome; long-term; low FODMAP diet; quality of life; questionnaire.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Cross-Sectional Studies
  • Diet, Carbohydrate-Restricted / methods
  • Diet, Carbohydrate-Restricted / psychology*
  • Disaccharides
  • Female
  • Fermentation
  • Humans
  • Irritable Bowel Syndrome / diet therapy*
  • Irritable Bowel Syndrome / psychology
  • Male
  • Middle Aged
  • Monosaccharides
  • Oligosaccharides
  • Patient Compliance / psychology
  • Patient Compliance / statistics & numerical data*
  • Patient Satisfaction
  • Polymers
  • Quality of Life
  • Retrospective Studies
  • Surveys and Questionnaires
  • Time
  • Young Adult


  • Disaccharides
  • Monosaccharides
  • Oligosaccharides
  • Polymers
  • polyol