Review📅 30.04.2026🤖 AI Research

Network meta-analysis of 10 RCTs (n=939): MED-LFD leads in IBS with P-score 0.76

A fresh preprint dated April 1, 2026 pooled 10 randomized clinical trials and for the first time systematically compared the five most popular diets for irritable bowel syndrome (IBS). The winner is the Mediterranean and low-FODMAP combination (MED-LFD): P-score 0.76 out of 1.00. Classic low-FODMAP remains a reliable first line, while a gluten-free diet only fits a narrow group of patients.

What was studied

The authors searched PubMed, Embase, Cochrane Library and Web of Science and selected all RCTs published between 2019 and 2025 comparing dietary interventions in adult IBS patients. Risk of bias was assessed using Cochrane RoB 2.0, and diets were compared via network meta-analysis (NMA) — which can rank interventions even when they haven't been compared head-to-head in a single trial.

The final analysis included 10 RCTs and 939 participants. Five diets were compared:

• LFD — low-FODMAP (excluding fermentable oligo-, di-, monosaccharides and polyols);
• MD — Mediterranean diet;
• MED-LFD — hybrid of Mediterranean and low-FODMAP;
• SSRD — starch and sucrose-restricted diet;
• TDA — traditional dietary advice (classic guidance on schedule, fiber and triggers);
• GFD — gluten-free diet.

The control was "habitual diet" without intervention.

The main result

All five active diets significantly outperformed the control. The NMA produced a P-score ranking (probability of being the best intervention — closer to 1.00 is better):

Node-splitting analysis showed no local inconsistency in the network (p > 0.05 for all nodes) — meaning direct and indirect comparisons agree, and the ranking can be trusted within the included data.

Each diet has its own profile of efficacy, tolerability and safety: low-FODMAP is best clinically validated, MED-LFD wins on long-term outcomes, TDA is easier to follow but produces a smaller effect, and GFD is justified only in specific subgroups (e.g., confirmed non-celiac gluten sensitivity).

What this means for you

If you have IBS, a logical strategy based on this NMA looks like:

1. Step 1 — traditional dietary advice (TDA). Regular meals, limited caffeine, alcohol, fatty and spicy foods, smaller portions, adequate fiber. Produces a moderate effect without strict restrictions.
2. If TDA doesn't help, move to low-FODMAP (LFD) for 4-6 weeks under dietitian supervision, with a structured reintroduction phase. This is the most studied and predictable option.
3. For long-term control, consider MED-LFD or MD. The Mediterranean pattern is easier to maintain over months and years, and combined with low-FODMAP principles it tops the efficacy ranking.
4. Don't start a gluten-free diet "just in case" — without lab confirmation of celiac disease or non-celiac gluten sensitivity, it doesn't outperform other approaches and needlessly restricts the diet.

Any elimination diet (LFD, MED-LFD, SSRD) should be done with a specialist — long-term self-elimination of FODMAP foods depletes the microbiota and reduces dietary diversity.

Important caveats

• Modest sample size. 10 RCTs and 939 participants is on the low end for NMA: some comparisons rest on just one or two studies.
• Short follow-up. Most RCTs ran 4-12 weeks; long-term effects (>6 months) on symptoms and microbiota remain poorly studied.
• Diagnostic heterogeneity. IBS subtypes (diarrhea-predominant, constipation, mixed) respond differently to diet — the overall ranking doesn't guarantee equal benefit for everyone.
• Limited authorship. Europe PMC metadata lists a single author (Yang X.), which is unusual for an NMA — the peer-reviewed version may be revised.
• This is a preprint. Results haven't been peer-reviewed yet and may change on journal publication.