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Does the low FODMAP diet help irritable bowel syndrome?

A low FODMAP diet eased IBS symptoms, belly pain and bloating in several trials and meta-analyses. Long-term results are less clear.

Published October 2026

Short answer

The low FODMAP diet eases IBS symptoms, belly pain and bloating more than a habitual diet, but the long-term benefit is less clear and the diet is restrictive. Evidence grade B (Moderate). Network meta-analyses of 13 and 28 randomised trials favour the diet; downgraded for risk of bias because diet trials cannot be fully blinded.

Key takeaways

  • A 2025 network meta-analysis of 28 trials (2,338 people) found the low FODMAP diet beat a habitual diet for global IBS symptoms, abdominal pain and bloating [1].
  • In a 2022 trial, traditional dietary advice worked about as well as the low FODMAP diet, so the diet is not clearly superior to all alternatives [2].
  • Benefits lasted in a 2017 trial when foods were reintroduced, but a 12-month follow-up found the standard diet's benefit had faded [3][4].
  • On the diet, fibre intake fell in one trial, so it needs planning [3].

The short version

The low FODMAP diet can ease irritable bowel syndrome (IBS) symptoms, belly pain and bloating more than a habitual diet [1][5]. Its long-term benefit is less clear, and the diet can be hard to follow [4][6].

What the studies show

The largest pooled result is a 2025 network meta-analysis of 28 trials with 2,338 people. Compared with a habitual diet, people on the low FODMAP diet were about half as likely to have global symptoms that did not improve (RR 0.51) [1]. The same analysis found less abdominal pain (RR 0.61) and less bloating (RR 0.55) [1].

A 2022 network meta-analysis of 13 trials with 944 people ranked the diet first for global symptoms against a habitual diet [5]. Single trials agree. In a 3-week crossover trial of 30 people with IBS, symptom scores were about half as high on a low FODMAP diet as on a typical Australian diet, 22.8 against 44.9 mm [7].

Other diets did about as well in some trials. A 2022 trial found 42% of people on traditional dietary advice responded, against 55% on the low FODMAP diet and 58% on a gluten-free diet, a difference that was not significant [2]. A 2024 three-arm trial of 294 people found 76% on the low FODMAP diet plus standard advice responded, against 58% on medication [8].

The nuances

Some people respond more than others. In one crossover trial, a third of people responded, and symptom severity helped predict who [9].

Benefits can last. In a 2017 trial, symptom scores stayed lower for 6 months, including after some high-FODMAP foods were added back [3]. In a 12-month follow-up, the standard diet's benefit had faded, while a personalised diet kept its improvement [4]. That follow-up is hypothesis-generating, and its authors include people linked to the company that developed the personalised approach [4].

The diet cuts fibre and does not clearly change overall gut bacteria. Fibre intake fell from 33 to 21 grams a day in one trial, and rose again after reintroduction [3]. Across nine trials, the diet consistently lowered Bifidobacteria, but overall diversity did not clearly change, and what that means for health is not known [10].

Not every high-FODMAP food causes trouble. In a 2025 reintroduction trial of 21 people, fructans and galacto-oligosaccharides were linked to worse abdominal pain [6].

The evidence quality is limited. Diet trials are hard to blind, and most were run in secondary or tertiary care [5]. In the 2024 three-arm trial, no serious adverse events occurred [8].

What this means for you

The low FODMAP diet is one of the best-studied diets for IBS, and pooled trials point to real symptom relief for many people [1]. Because it is restrictive and its long-term benefit is less clear, many people use it as a short trial and then add foods back [3]. Talk with a doctor or dietitian before you start, especially if you are considering it long term.

Go deeper

  • Low FODMAP Diet — The low FODMAP diet eases irritable bowel syndrome symptoms, belly pain and bloating more than a habitual diet in pooled trials.

References

  1. Efficacy of dietary interventions in irritable bowel syndrome: a systematic review and network meta-analysis.. Lancet Gastroenterol Hepatol, 2025.
  2. Efficacy and Acceptability of Dietary Therapies in Non-Constipated Irritable Bowel Syndrome: A Randomized Trial of Traditional Dietary Advice, the Low FODMAP Diet, and the Gluten-Free Diet.. Clin Gastroenterol Hepatol, 2022.
  3. Long-term irritable bowel syndrome symptom control with reintroduction of selected FODMAPs.. World J Gastroenterol, 2017.
  4. Long-term microbiome and clinical effects of a microbiome-guided personalized diet versus low-FODMAP diet in irritable bowel syndrome: A 12-month follow-up randomized controlled trial.. Gut Microbes, 2026.
  5. Efficacy of a low FODMAP diet in irritable bowel syndrome: systematic review and network meta-analysis.. Gut, 2022.
  6. All FODMAPs Aren't Created Equal: Results of a Randomized Reintroduction Trial in Patients With Irritable Bowel Syndrome.. Clin Gastroenterol Hepatol, 2025.
  7. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome.. Gastroenterology, 2014.
  8. A low FODMAP diet plus traditional dietary advice versus a low-carbohydrate diet versus pharmacological treatment in irritable bowel syndrome (CARIBS): a single-centre, single-blind, randomised controlled trial.. Lancet Gastroenterol Hepatol, 2024.
  9. Low FODMAP diet reduces gastrointestinal symptoms in irritable bowel syndrome and clinical response could be predicted by symptom severity: A randomized crossover trial.. Clin Nutr, 2022.
  10. Effects of a low FODMAP diet on the colonic microbiome in irritable bowel syndrome: a systematic review with meta-analysis.. Am J Clin Nutr, 2022.