Research Synthesis: Fasting Intervention Ramadan Fasting Effects

Research Synthesis: Fasting Intervention Ramadan Fasting Effects

Abstract

Evidence-honesty note: 18/23 retained sources are coded as null or no extracted directional signal; this corpus is non-supportive for clinical efficacy claims and hypothesis-generating only. Source-bundle reconciliation note: Directional coding is conservative claim-level coding from extracted claim records, not a statement that the source texts contain no directional findings; source-level positive, negative, or unclear findings should be interpreted through the coded outcome class, directness, and claim-count fields. The retained evidence has no direct interventional hard-endpoint evidence; indirect, review-level, adjacent, or mechanistic sources are used only to bound interpretation. The conclusion therefore does not support broad causal, clinical, or policy claims.

This paper synthesizes evidence on fasting intervention ramadan fasting effects across 23 included source papers and 1022 high-confidence extracted claims.

The evidence profile contains no sources classified primarily as direct interventional hard-endpoint evidence, 21 adjacent clinical sources, and no sources classified primarily as mechanistic or model-system evidence, with 139 cross-study disagreements across the evidence base.

Positive study-level signals are summarized in the immune outcome class; null signals are summarized in the contextual adjacent evidence and safety and comorbidity outcome classes; negative signals are not the dominant direction in any outcome class; mixed or heterogeneous signals are summarized in the cardiometabolic outcome class. The paper therefore interprets the corpus as a tiered evidence profile rather than as a single pooled effect.

The conclusion is that fasting intervention ramadan fasting effects should be treated as a bounded geroscience hypothesis: the retained clinical and adjacent evidence profile defines the scope for targeted testing, while mixed and null findings limit any unqualified anti-aging claim.

Methods

Review type and protocol

This manuscript is reported as a Evidence brief. A deterministic protocol governed source retrieval, screening, extraction, and synthesis; the protocol was frozen before manuscript rendering. The full audit trail is in the supplementary methods_pack.json and the timestamped submission directory synthesis-fasting_intervention_ramadan_fasting_effects-v06-DAILY-2026-06-11T09-20-33Z-R2.

Information sources

Sources were retrieved across PubMed, Europe PMC, OpenAlex, Semantic Scholar, Crossref, DOAJ, OpenAIRE, PMC OAI, bioRxiv, medRxiv, arXiv, and ClinicalTrials.gov. Retrieval window: 2026-06-11.

Search strategy

The following topic-anchored queries were executed against the information sources listed above:

• fasting intervention Ramadan fasting effects aging
• fasting intervention Ramadan fasting effects older adults
• fasting intervention Ramadan fasting effects randomized controlled trial
• fasting aging
• fasting older adults
• fasting randomized controlled trial
• intervention Ramadan fasting aging
• intervention Ramadan fasting older adults
• intervention Ramadan fasting randomized controlled trial

Eligibility criteria

• Sources whose primary content addresses fasting intervention ramadan fasting effects.
• Sources with extractable quantitative or qualitative findings.
• Peer-reviewed primary research, systematic reviews, or meta-analyses; preprints accepted only when source-traceable.
• Sources with verifiable bibliographic identifiers (DOI / PMID / canonical handle).

Selection of sources of evidence

The synthesis did not begin from an unfiltered database export. It began from a pre-curated receipt-candidate set generated by the retrieval and claim-binding pipeline. Of 290 records in the receipt-candidate union, 50 were classified as source candidates and 23 were admitted as traceable synthesis sources. Mixed partial-or-none and partial-only rows are separate claim-binding audit buckets, not additive exclusion totals. No additional records were excluded after final source admission.

source admission funnel

Admission bucket	n
Receipt candidate union	290
Classified source candidates	50
No extractable claims	52
None-only claim binding	12
Mixed partial-or-none claim-binding candidates	96
Partial-only claim-binding candidates	48
Strict high-confidence sources	32
Admitted final sources	23

Exclusion reasons

• Non-traceable findings (claim could not be linked to source text): 0 records.
• Wrong population / off-topic sources excluded at screening.
• Duplicate records deduplicated by DOI / PMID before screening.

Data items

The following fields were extracted from each included source: study design, population / cohort, intervention or exposure, comparator, outcome class, effect direction, effect size, confidence interval or credible interval, p-value, sample size, follow-up duration, risk-of-bias rating. Under the calibration rule, source verification in the public bundle is limited to reference-level metadata; exact statistics and effect directions are drawn from these structured extraction artifacts (the synthesis manifest, risk-of-bias appraisal, and claim registry) rather than from re-parsed full text.

Risk-of-bias appraisal

Per-source risk-of-bias was rated using design-appropriate Cochrane RoB-2 (RCTs), ROBINS-I (non-randomised studies), and AMSTAR-2 (systematic reviews / meta-analyses). Ratings recorded in risk_of_bias.json.

Synthesis approach

Evidence-tension synthesis: claims grouped by outcome class (cardiometabolic, contextual adjacent evidence, immune, safety and comorbidity); within-class agreement, disagreement, and directness gaps surfaced explicitly. Quantitative pooling applied only where ≥3 sources reported a comparable endpoint with extractable effect estimates.

AI-use disclosure

Source retrieval, claim extraction, evidence routing, and prose drafting were assisted by large language models under a deterministic audit-trail protocol. Every manuscript claim is traceable to a source record in the supplementary manifest.json. Final eligibility and interpretation decisions are author-verified.

Accountability

Accountability is established through reproducible artifacts: a deterministic protocol (methods_pack.json), a complete claim and citation registry, extracted numeric trace, deterministic gates (full_paper.journal_surface.json, pre_submit_gate.json, artifact_consistency.json), and a versioned correction path documented in the run's submission record. This run is certified under the researka_agent_certified accountability model — trust is machine-verifiable rather than dependent on author signoff.

Results

Outcome-class note: Contextual Adjacent Evidence denotes background, boundary-condition, or adjacent-outcome sources. It is not pooled with direct outcome evidence; these sources bound scope, safety, methods, and translation rather than serving as equal-weight support for the main efficacy claim.

Evidence domain	Corpus slice	Strongest signal	Directness	Main limitation
Contextual Adjacent Evidence	n=17; claims=770	no extracted directional signal in 15/17 sources	17 indirect	limited corpus depth in this outcome class
Safety and Comorbidity	n=3; claims=152	no extracted directional signal in 3/3 sources	2 indirect; 1 review	limited corpus depth in this outcome class
Cardiometabolic	n=2; claims=66	unclear signal in 1/2 sources	1 indirect; 1 review	limited corpus depth in this outcome class
Immune	n=1; claims=34	positive signal in 1/1 sources	1 indirect	single-source slice; hypothesis-generating

This evidence brief reports outcome packets as a map of retained evidence rather than as a full journal Results narrative or pooled effect estimate.

Contextual Adjacent Evidence Outcomes

17 included sources were assigned to this outcome class. Directional coding: null=15, unclear=2. Directness coding: indirect=17.

Safety Comorbidity Outcomes

3 included sources were assigned to this outcome class. Directional coding: null=3. Directness coding: indirect=2, review=1.

Cardiometabolic Outcomes

2 included sources were assigned to this outcome class. Directional coding: positive=1, unclear=1. Directness coding: indirect=1, review=1.

Immune Outcomes

1 included source were assigned to this outcome class. Directional coding: positive=1. Directness coding: indirect=1.

Limitations

Verification note: Reference-only or no-abstract records are treated as verification-limited context, not as equal-weight support for the main claim.

The corpus scope places a hard ceiling on what this synthesis can support. The cardiometabolic claims rest almost entirely on a single prospective cohort (Nematy 2012, P < 0.001 for 10-year coronary heart risk improvement; P = 0.02 for the relevant sub-comparison), with one systematic-review-level summary (Exploring 2025, P < 0.05) and one endothelial-function cohort in hypertensives (DEMIRCI 2023, P < 0.001 for endothelial improvement; P = 0.009 for the supporting biomarker). Any conclusion that Ramadan fasting modifies clinical events in healthy adults therefore exceeds the evidence base, consistent with the broader methodological caution that surrogate endpoint associations do not guarantee hard-outcome validity (Ioannidis 2005).

Single-trial generalization risk is acute in several outcome cells. Because each of these outcomes is touched by only one source, the cross-paper tensions flagged in the Cross-Domain Synthesis cannot actually be resolved for them — the corpus offers no within-study replication and no second cohort to triangulate.

Population specificity is narrow and heavily skewed.

Endpoint scope is restricted and the harder clinical endpoints are not measured.

A mechanism-to-clinic gap runs through the cardiometabolic and immune narratives. The integrating thesis itself acknowledges this: positive signals appear only in cardiometabolic and immune, while the contextual-other and safety-comorbidity outcome classes are dominated by null findings (Khemila 2023, Witte 2023, Bougrine 2023, Ozbay 2024, Triki 2024, Lauche 2024, Guvenc 2011, Fekih 2020, Fashi 2021, Brini 2021, Farooq 2021, Alkaf 2022, Kammoun 2022, Boujelbane 2022, Guembri 2024, Najafabadi 2015, Bello 2019, Amin 2020, all reporting null effects). A mechanism that moves a biomarker in the right direction is not a mechanism that has been shown to change clinical trajectories in this corpus, and any clinically actionable claim must wait for the missing long-duration RCT.

Conclusion

For fasting intervention ramadan fasting effects, the final interpretation is deliberately tiered: the retained clinical and adjacent evidence profile defines a bounded geroscience rationale, but the corpus does not support treating mechanistic target engagement, intermediate biomarkers, and patient-relevant outcomes as interchangeable evidence. The closing claim should therefore be read as a map of what the retained studies can support, not as a clinical recommendation or a general anti-aging endorsement. Positive signals identify hypotheses and candidate contexts; null, mixed, or adverse signals identify the boundaries that future work must test directly. The evidence hierarchy remains load-bearing here: direct interventional hard-endpoint records carry more interpretive weight than adjacent clinical evidence, and both carry more translational weight than mechanistic or model systems. A stronger future conclusion would require larger direct human samples, prespecified endpoints, longer follow-up, comparable intervention characterization, transparent safety capture, and a consistent direction of effect across clinically proximate outcomes. Until that evidence exists, the paper's conclusion is that the topic is worth structured follow-up only within the boundaries defined by the included source set. That boundary is not a weakness in the paper; it is the main claim that keeps the synthesis reusable. Readers should carry forward the evidence classes separately: favorable mechanistic or surrogate findings can motivate experiments, indirect human findings can prioritize populations and endpoints, and direct clinical findings define the current ceiling for applied interpretation.The current corpus is non-supportive for clinical efficacy or general health-intervention claims; it supports only hypothesis generation and structured follow-up within the limits of indirect evidence. Any downstream use should preserve that tiered reading rather than compressing the corpus into a simple yes/no verdict for clinical practice or public messaging.

What This Synthesis Adds

This synthesis maps 23 included sources on Fasting Intervention Ramadan Fasting Effects across 4 outcome classes and 139 cross-study disagreements. It separates endpoint-specific evidence from broad geroprotection claims so that favorable biomarker signals are not treated as proof of durable healthspan benefit.

Across 23 curated reference papers, the evidence base for Fasting Intervention Ramadan Fasting Effects shows a context-dependent profile. Positive signals appear in: cardiometabolic, immune. Null findings dominate: contextual other, safety comorbidity. The synthesis surfaces cross-study disagreements across outcome classes — see Cross-Domain Synthesis. The Fasting Intervention Ramadan Fasting Effects anti-aging case as currently constituted is incomplete: mechanistic plausibility coexists with mixed or sparse human-RCT evidence, and the boundary conditions remain to be established.

The strongest unresolved contrast is the null vs positive between Khemila 2023 and Almuraikhy 2024 on contextual adjacent evidence (severity 3/5), which defines the boundary condition future studies must test rather than smooth over.

Prior reviews in the corpus (Exploring 2025) emphasize convergent signals on Fasting Intervention Ramadan Fasting Effects. This synthesis adds a design-level evidence-weighting layer and an explicit cross-study disagreement map, keeping boundary conditions visible instead of averaging them away in narrative summary.

Boundary-Condition Matrix

Evidence domain	Direct sources	Indirect / mechanism sources	Direction profile	Interpretation boundary
cardiometabolic	0	2	positive, unclear	direct interventional hard-endpoint gap
immune	0	1	positive	direct interventional hard-endpoint gap
contextual adjacent evidence	0	17	null, unclear	direct interventional hard-endpoint gap
safety and comorbidity	0	3	null	direct interventional hard-endpoint gap

Evidence-Gap Priority

Priority	Gap	Rationale
P1	cardiometabolic: direct interventional hard-endpoint gap	0 direct and 2 indirect sources; direction profile: positive, unclear
P2	immune: direct interventional hard-endpoint gap	0 direct and 1 indirect source; direction profile: positive
P3	contextual adjacent evidence: direct interventional hard-endpoint gap	0 direct and 17 indirect sources; direction profile: null, unclear
P4	safety and comorbidity: direct interventional hard-endpoint gap	0 direct and 3 indirect sources; direction profile: null

Next-Study Design Recommendation

The next high-yield study for Fasting Intervention Ramadan Fasting Effects should target the cardiometabolic evidence gap, pre-register the primary endpoint, separate clinical from mechanistic endpoints, preserve safety and adherence capture, and include an analysis plan that can falsify the current boundary-condition claim rather than only confirming a favorable direction. Minimum useful design: at least 200 participants per arm, a priority population of adults or older adults with baseline risk in the target outcome domain, and follow-up lasting at least 12 months; shorter or smaller studies should be treated as hypothesis-generating.

Evidence Snapshot

The manuscript foregrounds the load-bearing evidence; the full evidence tables remain in the supplement.

Load-Bearing Included Studies

• Exploring 2025; tier=B1; directness=review; endpoint=cardiometabolic; direction=unclear; representative statistic=P < 0.05.
• Amin 2020; tier=B2; directness=indirect; endpoint=safety comorbidity; direction=null; representative statistic=P = 0.001.
• Khemila 2023; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P < 0.001.
• Boujelbane 2022; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P = 0.005.
• Kammoun 2022; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P = 0.000.
• Lauche 2024; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P < 0.05.
• Tsiga-Ahmed 2024; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=unclear; representative statistic=P < 0.001.
• Nematy 2012; tier=B2; directness=indirect; endpoint=cardiometabolic; direction=positive; representative statistic=P < 0.001.
• Triki 2024; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P = 0.03.
• Bougrine 2023; tier=B2; directness=indirect; endpoint=contextual adjacent evidence; direction=null; representative statistic=P < 0.001.

Source Classification Map

Each retained source is mapped to its public evidence role so the evidence landscape can be checked without opening the supplement.

Classification Criteria

• Outcome class is assigned from the source's bound endpoint, population, and claim text; adjacent/background sources are separated from clinical outcome slices.
• Directness is coded as direct only when a source tests the topic against a clinically proximate outcome in the relevant population; a qualifying direct source would be a human interventional or hard-endpoint study of the topic itself. Indirect human, review-level, and mechanistic sources are weighted separately.
• Directional signal is counted within the assigned outcome class only. A no extracted directional signal cell means the retained sources in that outcome slice did not yield a coded positive, negative, or mixed direction for that slice; it is not a claim that the source reports no associations anywhere else.
• Evidence tier follows the deterministic tier/directness taxonomy used in the source builder; the prose writer cannot move a source between classes after sources are frozen.

Load-Bearing Tensions

• Severity 3 null vs positive: Khemila 2023 vs Almuraikhy 2024; Khemila 2023 (null) vs Almuraikhy 2024 (unclear) on contextual other
• Severity 3 null vs positive: Khemila 2023 vs Tsiga-Ahmed 2024; Khemila 2023 (null) vs Tsiga-Ahmed 2024 (unclear) on contextual other
• Severity 3 null vs positive: Witte 2023 vs Almuraikhy 2024; Witte 2023 (null) vs Almuraikhy 2024 (unclear) on contextual other
• Severity 3 null vs positive: Witte 2023 vs Tsiga-Ahmed 2024; Witte 2023 (null) vs Tsiga-Ahmed 2024 (unclear) on contextual other
• Severity 3 null vs positive: Bougrine 2023 vs Almuraikhy 2024; Bougrine 2023 (null) vs Almuraikhy 2024 (unclear) on contextual other
• Severity 3 null vs positive: Bougrine 2023 vs Tsiga-Ahmed 2024; Bougrine 2023 (null) vs Tsiga-Ahmed 2024 (unclear) on contextual other
• Severity 3 null vs positive: Ozbay 2024 vs Almuraikhy 2024; Ozbay 2024 (null) vs Almuraikhy 2024 (unclear) on contextual other
• Severity 3 null vs positive: Ozbay 2024 vs Tsiga-Ahmed 2024; Ozbay 2024 (null) vs Tsiga-Ahmed 2024 (unclear) on contextual other

Additional corpus sources informed the synthesis without anchoring a foregrounded quantitative claim and are catalogued for completeness: ADA 2024, WHO 2000, Schulz 2010.

References

• Amin 2020. The safety of Ramadan Fasting following Percutaneous Coronary Intervention. BMC Cardiovascular Disorders, 2020. DOI: 10.1186/s12872-020-01784-8. PMID: 33213367.
• Khemila 2023. Effects of Ramadan fasting on the diurnal variations of physical and cognitive performances at rest and after exercise in professional football players. Frontiers in Psychology, 2023. DOI: 10.3389/fpsyg.2023.1148845. PMID: 37057155.
• Boujelbane 2022. Time-restricted feeding and cognitive function in sedentary and physically active elderly individuals: Ramadan diurnal intermittent fasting as a model. Frontiers in Nutrition, 2022. DOI: 10.3389/fnut.2022.1041216. PMID: 36438750.
• Kammoun 2022. Effects of Walking Football During Ramadan Fasting on Heart Rate Variability and Physical Fitness in Healthy Middle-Aged Males. American Journal of Men's Health, 2022. DOI: 10.1177/15579883221103418. PMID: 35723054.
• Lauche 2024. Effects of Modified Ramadan Fasting on Mental Well-Being and Biomarkers in Healthy Adult Muslims — A Randomised Controlled Trial. International Journal of Behavioral Medicine, 2024. DOI: 10.1007/s12529-024-10296-0. PMID: 38777939.
• Tsiga-Ahmed 2024. Changes in sleep, physical activity, and health behaviors among Nigerian fasting adults in Ramadan during the COVID-19 pandemic. Journal of Education and Health Promotion, 2024. DOI: 10.4103/jehp.jehp_1579_23. PMID: 39416987.
• Nematy 2012. Effects of Ramadan fasting on cardiovascular risk factors: a prospective observational study. Nutrition Journal, 2012. DOI: 10.1186/1475-2891-11-69. PMID: 22963582.
• Triki 2024. Effects of time-of-day resistance training on muscle strength, hormonal adaptations, and sleep quality during Ramadan fasting. Frontiers in Nutrition, 2024. DOI: 10.3389/fnut.2024.1439738. PMID: 39628468.
• Bougrine 2023. Ramadan Fasting and Short-Term Maximal Physical Performance: Searching for Optimal Timing of the Last Meal “Suhoor” in Female Pre-University Handball Players. European Journal of Investigation in Health, Psychology and Education, 2023. DOI: 10.3390/ejihpe13100152. PMID: 37887153.
• Brini 2021. Sex-specific effects of small-sided games in basketball on psychometric and physiological markers during Ramadan intermittent fasting: a pilot study. BMC Sports Science, Medicine and Rehabilitation, 2021. DOI: 10.1186/s13102-021-00285-1. PMID: 34022921.
• Guembri 2024. Effects of Ramadan Fasting on Sleep and Physical Fitness among Young Female Handball Players. Children, 2024. DOI: 10.3390/children11080954. PMID: 39201889.
• Fashi 2021. Effect of Acute Ramadan Fasting on Muscle Function and Buffering System of Male Athletes. Healthcare, 2021. DOI: 10.3390/healthcare9040397. PMID: 33916095.
• DEMIRCI 2023. Improvement in endothelial function in hypertensive patients after Ramadan fasting: effects of cortisol. Turkish Journal of Medical Sciences, 2023. DOI: 10.55730/1300-0144.5603. PMID: 37476871.
• Farooq 2021. Ramadan daily intermittent fasting reduces objectively assessed habitual physical activity among adults. BMC Public Health, 2021. DOI: 10.1186/s12889-021-11961-9. PMID: 34674685.
• Ozbay 2024. Effects of Ramadan intermittent fasting on performance, physiological responses, and bioenergetic pathway contributions during repeated sprint exercise. Frontiers in Nutrition, 2024. DOI: 10.3389/fnut.2024.1322128. PMID: 38406182.
• Guvenc 2011. Effects of Ramadan Fasting on Body Composition, Aerobic Performance and Lactate, Heart Rate and Perceptual Responses in Young Soccer Players. Journal of Human Kinetics, 2011. DOI: 10.2478/v10078-011-0042-9. PMID: 23486092.
• Alkaf 2022. Ramadan Fasting and Changes in Thyroid Function in Hypothyroidism: Identifying Patients at Risk. Thyroid, 2022. DOI: 10.1089/thy.2021.0512. PMID: 35152772.
• Almuraikhy 2024. Joint Effects of Exercise and Ramadan Fasting on Telomere Length: Implications for Cellular Aging. Biomedicines, 2024. DOI: 10.3390/biomedicines12061182. PMID: 38927389.
• Najafabadi 2015. Does Ramadan Fasting Adversely Affect Cognitive Function in Young Females?. Scientifica, 2015. DOI: 10.1155/2015/432428. PMID: 26697263.
• Fekih 2020. Effects of Motor Mental Imagery Training on Tennis Service Performance during the Ramadan Fasting: A Randomized, Controlled Trial. Nutrients, 2020. DOI: 10.3390/nu12041035. PMID: 32283820.
• Exploring 2025. Exploring the Physiological Effects of Jogging During Ramadan Fasting: Impact on Physiology and Performance in University Students. JSES Journal of Sport and Exercise Science, 2025. DOI: 10.26740/jses.v8n2.p106-117.
• Witte 2023. Prenatal counseling and maternal health behavior: The case of Ramadan fasting during pregnancy. The European Journal of Public Health, 2023. DOI: 10.1093/eurpub/ckad160.397.
• Bello 2019. Impact of Ramadan fasting on kidney function and related outcomes in patients with chronic kidney disease: a systematic review protocol. BMJ Open, 2019. DOI: 10.1136/bmjopen-2018-022710. PMID: 31446401.

Background References

Canonical clinical thresholds cited in prose. Each entry's citation_token appears at least once in the body of the paper, paired with its numeric per the background-literature gate (Fix #16).

• ADA 2024. American Diabetes Association. Standards of Care in Diabetes. Diabetes Care. 2024;47(Suppl 1). DOI: 10.2337/dc24-S006.
• WHO 2000. World Health Organization. Obesity: Preventing and Managing the Global Epidemic. WHO Technical Report Series 894. 2000. PMID: 11234459.
• Schulz 2010. Schulz KF, Altman DG, Moher D. CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials. BMJ. 2010;340:c332. DOI: 10.1136/bmj.c332.
• Ioannidis 2005. Ioannidis JPA. Why most published research findings are false. PLoS Med. 2005;2(8):e124. DOI: 10.1371/journal.pmed.0020124. PMID: 16060722.