{ "format_version": 3, "claim_formal": { "subject": "Intermittent fasting", "sub_claims": [ { "id": "SC1", "property": "scientifically proven superior to other diets for fat loss", "operator": ">=", "threshold": 2, "operator_note": "SC1 is proved (for disproof purposes) when at least 2 independent peer-reviewed systematic reviews or meta-analyses conclude that IF does NOT significantly outperform isocaloric continuous caloric restriction for fat loss. A source counts if its verified quote expresses 'no significant difference,' 'not superior,' or equivalent. Threshold of 2 provides independent confirmation from separate publications." }, { "id": "SC2", "property": "scientifically proven superior to other diets for longevity in humans", "operator": ">=", "threshold": 2, "operator_note": "SC2 is proved (for disproof purposes) when at least 2 independent sources \u2014 peer-reviewed reviews or major clinical/scientific bodies \u2014 explicitly state that evidence for IF's longevity benefit in humans is lacking, insufficient, or unproven, OR that IF was not associated with longer lifespan in human observational data. Threshold of 2 provides independent confirmation." } ], "compound_operator": "AND", "proof_direction": "disprove", "operator_note": "The original claim asserts BOTH (a) proven fat loss superiority AND (b) proven longevity superiority. An AND claim is false if either conjunct is false. This proof shows both conjuncts fail: (a) meta-analyses show IF produces equivalent \u2014 not superior \u2014 fat loss vs. matched caloric restriction, and (b) no adequate human evidence exists for longevity superiority. proof_direction='disprove': empirical_facts sources REJECT each sub-claim; claim_holds=True triggers verdict DISPROVED (not PROVED)." }, "claim_natural": "Intermittent fasting is scientifically proven superior to other diets for fat loss and longevity.", "evidence": { "B1": { "type": "empirical", "label": "SC1-A: Systematic review & meta-analysis of IF vs. caloric restriction (PMC11930668, 2025) \u2014 weight loss difference not statistically significant", "sub_claim": "SC1", "source": { "name": "Evaluation of the effectiveness of intermittent fasting versus caloric restriction in weight loss and improving cardiometabolic health: A systematic review and meta-analysis (PMC, 2025)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC11930668/", "quote": "IF resulted in a slightly greater, but statistically nonsignificant, decrease in weight" }, "verification": { "status": "verified", "method": "full_quote", "coverage_pct": null, "fetch_mode": "live", "credibility": { "domain": "nih.gov", "source_type": "government", "tier": 5, "flags": [], "note": "Government domain (.gov)" } }, "extraction": { "value": "verified", "value_in_quote": true, "quote_snippet": "IF resulted in a slightly greater, but statistically nonsignificant, decrease in" } }, "B2": { "type": "empirical", "label": "SC1-B: Meta-analysis of IF vs. caloric restriction in humans (PMC9108547, 2022) \u2014 IF outcomes did not differ from CR", "sub_claim": "SC1", "source": { "name": "Effects of Intermittent Fasting in Human Compared to a Non-intervention Diet and Caloric Restriction: A Meta-Analysis of Randomized Controlled Trials (PMC, 2022)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9108547/", "quote": "IF outcomes did not differ from CR except for reduced WC" }, "verification": { "status": "verified", "method": "full_quote", "coverage_pct": null, "fetch_mode": "live", "credibility": { "domain": "nih.gov", "source_type": "government", "tier": 5, "flags": [], "note": "Government domain (.gov)" } }, "extraction": { "value": "verified", "value_in_quote": true, "quote_snippet": "IF outcomes did not differ from CR except for reduced WC" } }, "B3": { "type": "empirical", "label": "SC2-A: Review of IF health benefits (PMC11262566, 2024) \u2014 human longevity studies are short-duration with high variability", "sub_claim": "SC2", "source": { "name": "Review Article: Health Benefits of Intermittent Fasting (PMC, 2024)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC11262566/", "quote": "reported human studies have been of short duration, and the baseline parameters of the study populations are highly variable" }, "verification": { "status": "verified", "method": "full_quote", "coverage_pct": null, "fetch_mode": "live", "credibility": { "domain": "nih.gov", "source_type": "government", "tier": 5, "flags": [], "note": "Government domain (.gov)" } }, "extraction": { "value": "verified", "value_in_quote": true, "quote_snippet": "reported human studies have been of short duration, and the baseline parameters " } }, "B4": { "type": "empirical", "label": "SC2-B: American Heart Association newsroom, 2024 \u2014 time-restricted eating not associated with living longer", "sub_claim": "SC2", "source": { "name": "American Heart Association newsroom: 8-hour time-restricted eating linked to a 91% higher risk of cardiovascular death (AHA, 2024)", "url": "https://newsroom.heart.org/news/8-hour-time-restricted-eating-linked-to-a-91-higher-risk-of-cardiovascular-death", "quote": "Limiting food intake to less than 8 hours per day was not associated with living longer" }, "verification": { "status": "verified", "method": "full_quote", "coverage_pct": null, "fetch_mode": "live", "credibility": { "domain": "heart.org", "source_type": "unknown", "tier": 2, "flags": [], "note": "Unclassified domain \u2014 verify source authority manually" } }, "extraction": { "value": "verified", "value_in_quote": true, "quote_snippet": "Limiting food intake to less than 8 hours per day was not associated with living" } }, "A1": { "type": "computed", "label": "SC1: count of verified rejection sources for fat loss superiority", "sub_claim": "SC1", "method": "count(verified SC1 rejection sources) = 2", "result": "2", "depends_on": [] }, "A2": { "type": "computed", "label": "SC2: count of verified rejection sources for longevity superiority", "sub_claim": "SC2", "method": "count(verified SC2 rejection sources) = 2", "result": "2", "depends_on": [] } }, "cross_checks": [ { "description": "SC1: independent peer-reviewed sources consulted on fat loss", "n_sources_consulted": 2, "n_sources_verified": 2, "sources": { "sc1_source_a": "verified", "sc1_source_b": "verified" }, "independence_note": "Sources are from separate publications (2022 meta-analysis PMC9108547 and 2025 systematic review PMC11930668) with different author teams and data sets.", "fact_ids": [] }, { "description": "SC2: independent sources consulted on human longevity evidence", "n_sources_consulted": 2, "n_sources_verified": 2, "sources": { "sc2_source_a": "verified", "sc2_source_b": "verified" }, "independence_note": "Sources are from separate institutions: a 2024 PMC review article (PMC11262566) and the American Heart Association newsroom reporting on a 2024 observational study of >20,000 US adults.", "fact_ids": [] } ], "adversarial_checks": [ { "question": "Do any meta-analyses clearly show IF is significantly and clinically superiorly effective for fat loss vs. calorie-matched CCR?", "verification_performed": "Searched: 'intermittent fasting significantly superior fat loss meta-analysis'; 'IF vs caloric restriction fat mass randomized controlled trial superiority'. Reviewed Nutrients 2024 (PMID 39458528), PMC11930668 (2025), PMC9099935 (2022), PMC9108547 (2022), and Lancet eClinicalMedicine umbrella review (2024).", "finding": "Some meta-analyses find modest statistically significant advantages in specific metrics (e.g., BMI in one study, insulin sensitivity in another), but no meta-analysis concludes IF is clearly clinically superior for overall fat loss. Nutrients 2024: 'FBS did not show superior long-term outcomes compared to CCR.' PMC11930668 2025: weight loss difference 'statistically nonsignificant.' The scientific literature consistently describes IF as equivalent \u2014 not proven superior \u2014 to matched caloric restriction for fat loss.", "breaks_proof": false }, { "question": "Is there any human randomized controlled trial demonstrating that IF significantly extends lifespan or healthspan beyond other diets?", "verification_performed": "Searched: 'intermittent fasting human lifespan RCT randomized controlled trial'; 'time-restricted eating longevity humans clinical trial'; 'IF longevity human evidence 2022 2023 2024'. Reviewed PMC11262566, PMC8932957, ScienceDirect S1568163724000928.", "finding": "No such RCT exists. All evidence for IF extending lifespan comes from animal models (C. elegans, Drosophila, mice). Human studies measure short-term metabolic proxies (weight, insulin, lipids), not lifespan. PMC11262566: 'reported human studies have been of short duration.' The most recent large observational study (AHA 2024, n>20,000) found that time-restricted eating was NOT associated with longer life, and was linked to 91% higher cardiovascular mortality.", "breaks_proof": false }, { "question": "Is the AHA 2024 study on TRE and cardiovascular mortality robust enough to count as evidence against longevity claims?", "verification_performed": "Searched: 'time-restricted eating AHA 2024 cardiovascular mortality limitations observational study confounders'; 'TRE longevity criticism 2024'. Reviewed Science Media Centre expert reactions and TCTMD debate coverage.", "finding": "The AHA 2024 abstract has limitations: it was observational (not an RCT), relied on only 2 days of dietary recall, and may have reverse causation (sick people may eat within a shorter window). However, for SC2 the key point is not that IF harms longevity, but that IF has NOT been proven to extend human lifespan. Even discounting the AHA study, SC2 source A (PMC11262566) independently establishes insufficient human longevity evidence.", "breaks_proof": false } ], "verdict": { "value": "DISPROVED", "qualified": false, "qualifier": null, "reason": null }, "key_results": { "n_holding": 2, "n_total": 2, "claim_holds": true, "sc1_holds": true, "sc2_holds": true, "proof_direction": "disprove" }, "generator": { "name": "proof-engine", "version": "1.0.0", "repo": "https://github.com/yaniv-golan/proof-engine", "generated_at": "2026-03-28" }, "proof_py_url": "/proofs/intermittent-fasting-is-scientifically-proven-supe/proof.py", "citation": { "doi": "10.5281/zenodo.19489791", "concept_doi": "10.5281/zenodo.19489790", "url": "https://proofengine.info/proofs/intermittent-fasting-is-scientifically-proven-supe/", "author": "Proof Engine", "cite_bib_url": "/proofs/intermittent-fasting-is-scientifically-proven-supe/cite.bib", "cite_ris_url": "/proofs/intermittent-fasting-is-scientifically-proven-supe/cite.ris" }, "depends_on": [] }