Meta-analysisindependent cross-checkfull text checked★ key study I-FAST-106 in-depth review
Fasting and joint disease activity
Intermittent fasting for rheumatic diseases: a systematic review and meta-analysis of conflicting evidence from observational studies and randomized controlled trials.
Overview
Liu R et al.. PeerJ 2026 · PMID 42079723 · DOI 10.7717/peerj.21185
In small studies, fasting slightly lowered rheumatoid arthritis activity scores; the evidence is weak.
Does the study support the specific claim? Partly · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Pool studies of intermittent fasting in rheumatic disease.
- How was the study done?
Systematic review and meta-analysis of 7 studies.
- How many people, animals or samples were studied?
556 patients with RA or spondyloarthritis.
- What was actually found?
DAS28 fell by 0.55 points in 2 RCTs; larger, less reliable falls in observational studies.
- How large was the observed effect?
DAS28 MD -0.55 (-1.09 to -0.02).
- What do the results mean in everyday life?
Fasting may help joint symptoms a little in some people with RA who keep taking their medicines.
- What are the study's limitations?
Very few small trials; mixed methods.
- What does it say about Elawady's specific claim?
Partly supports 'fasting treats joint pain'; does not support fasting as a treatment of autoimmune disease on its own.
- Do the results apply to Germany and Europe?
Applies; same physiology.
- What can explicitly not be concluded from this study?
Whether fasting can replace disease-modifying drugs (not tested).
Scientific in-depth review
1. Full reference
- Authors
- Liu R et al.
- Journal
- PeerJ
- Year
- 2026
- Identifier
- PMID 42079723 DOI 10.7717/peerj.21185
- Verification
- verified – PubMed efetch 2026-10-26; Crossref update-to/updated-by check
- Retracted
- no
- Corrections
- none
- Extent checked
- full text
- Conflicts of interest and funding
Authors declare no competing interests.
2. Research question
Does intermittent fasting improve disease activity and inflammatory markers in rheumatic diseases?
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis (RevMan, random effects)
- Population
Adults with rheumatoid arthritis (RA) or spondyloarthritis (SpA)
- Country
Studies from Italy, Iran, Tunisia, Germany, Morocco, Pakistan, France
- Period
Search to 15 March 2026
- Sample size
7 independent studies (9 datasets): 471 RA and 85 SpA patients; RCT subgroup 2 independent RCTs (3 publications), 94 participants
- Inclusion and exclusion criteria
Clinical studies of IF in rheumatic disease (Ramadan fasting, 16:8 TRE, fasting with bowel cleansing / plant-based diet)
4. Methods and endpoints
- Exposure / intervention
Intermittent fasting (Ramadan diurnal fasting, 16:8, 7-10-day fasting)
- Comparator
Pre-fasting values or control diet
- Endpoints
DAS28, VAS, CDAI, BASDAI, ESR, hs-CRP
- Statistical methods
Random-effects MD; I2
5. Actual results
- Results
Observational: VAS MD -1.71 (-2.60 to -0.82), DAS28 MD -1.05 (-1.36 to -0.73). RCT subgroup (94 participants): DAS28 MD -0.55 (95% CI -1.09 to -0.02), I2 0%; CDAI -3.71 (-11.35 to 3.93); ESR -5.94 (-12.52 to 0.64); hs-CRP -2.71 (-8.76 to 3.33), I2 92%.
- Absolute risks
not reported
- Authors' conclusion
Positive effect of IF on disease activity, but RCT reliability limited by small number of studies and heterogeneous interventions.
6. Strengths
- Recent comprehensive search
- Separates observational and randomised evidence
7. Weaknesses
- Only 2 independent RCTs (94 people)
- Abstract says 'three RCTs' while full text says two independent RCTs in three publications
- Heterogeneous fasting types; one RCT combined fasting with an 11-week plant-based diet
- Patients continued usual drug therapy
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- high
- Rationale
Few, small, heterogeneous studies; publication bias could not be assessed.
9. Assessment of the statistical interpretation
Small reduction in DAS28 in RCTs with CI upper bound near zero (-0.02); observational pre-post improvements are prone to regression to the mean and placebo effects. See stats/I-FAST-106_if_rheumatic.py.
10. Relevance to the specific claim
Supports a modest, low-certainty benefit of fasting on joint symptoms in RA as an add-on - not autoimmune cure and not replacement of medication.
11. Independent contrary findings
Cochrane 2009 on diet in RA found uncertain effects (not re-registered here).
12. Transferability to Germany and Europe
Includes North African (Tunisia, Morocco) Ramadan studies; directly relevant to Egypt.
13. Overall methodological judgement
Low-certainty support for the 'joint pain' part of the claim; patients remained on drug therapy.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | high |
| Precision of results | low |
| Directness | indirect |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |