A network meta-analysis pooled 10 randomized controlled trials from 2019–2025 and, for the first time, ranked five dietary approaches for irritable bowel syndrome by efficacy. The winner is the combination of the Mediterranean diet with low FODMAP (P-score 0.76). The laggard is standard dietary advice (P-score 0.20).
The research team searched PubMed, Embase, the Cochrane Library, and Web of Science. They included only RCTs in adults with diagnosed IBS (Rome III/IV criteria), published between 2019 and 2025. Study quality was assessed with the Cochrane RoB 2.0 tool, and statistics were calculated with random-effects modeling within the comparison network.
The final analysis included 10 studies and 939 participants. Five approaches were compared:
All specific diets outperformed standard advice. The P-score is the probability that an approach is more effective than a randomly chosen competitor: the closer to 1.0, the higher the chance of being the leader.
| Diet | P-score | What it means |
|---|---|---|
| MED-LFD (Mediterranean + low FODMAP) | 0.76 | Best for efficacy and long-term adherence |
| SSRD (low starch/sucrose) | 0.70 | A strong alternative to low FODMAP |
| MD (Mediterranean) | 0.68 | Good balance of effect and convenience |
| LFD (low FODMAP) | 0.60 | Reliable first-line choice, but hard to follow |
| TDA (standard advice) | 0.20 | Acceptable but less effective |
A node-splitting analysis confirmed the statistical consistency of the comparison network (P > 0.05) — meaning that direct and indirect comparisons do not contradict each other.
Key takeaway: Low FODMAP remains the evidence-based "first line," but enriching it with Mediterranean elements (olive oil, fish, nuts, FODMAP-adjusted legumes) boosts the effect and improves long-term adherence.
This network meta-analysis does not dismiss low FODMAP — it shows that a purely restrictive strategy is not always the best choice. Strict FODMAP exclusion works during the elimination phase (4–6 weeks) but is a poor fit for everyday life: the microbiome and dietary variety suffer.
What to discuss with your physician or dietitian if you have IBS:
This is a network meta-analysis of 10 trials and 939 people — smaller than the major meta-analyses for hypertension or diabetes. Most RCTs lasted 4–12 weeks: data on year-long adherence and durability of effect are still lacking.
In addition, MED-LFD is represented by fewer studies in the network than LFD, so its lead on the P-score needs confirmation in larger RCTs. And most importantly — this is a preprint: peer review may change the interpretation.
⚠ This is a preprint on Research Square — the publication has not undergone independent peer review. The figures and conclusions may shift after peer review. Before changing your diet for IBS, always consult a gastroenterologist.
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