Longevity & Aging · Metabolic & Cardiometabolic
periodic fasting-mimicking diet cycles decreases biological age composite clinical biomarker aging-clock score
In plain terms: Can monthly fasting-mimicking-diet cycles make you biologically younger?
Part of: • Fasting & Time-Restricted Eating
A few small trials report modestly younger 'biological age' markers from periodic fasting-mimicking-diet (FMD) cycles — with three honest caveats. First, much of this research comes from Valter Longo's lab, and Longo founded L-Nutra, the company that sells the ProLon FMD kit — a direct commercial interest in the result. Second, 'biological age' is a soft, contested lab surrogate (aging clocks), not a hard health outcome — and unlike major diet trials that hit hard endpoints (e.g. DiRECT's type-2-diabetes remission), FMD hasn't shown that. Third, the supporting trials are small and some are population-specific. Graded insufficient: the only positive signal comes from one commercially interested lab, and independent trials have not confirmed a biological-age change.
📅 Last reviewed: 2026-07-14 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
A Longo-lab secondary analysis reports about 2.5 years lower biological age on a validated clock after three fasting-mimicking cycles, with a further trial reversing markers of accelerated aging. Every supporting row comes from that one network, which is why this reads insufficient rather than supported, and the hepatocyte work is mechanistic only.
The evidence (5)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Shtark RB, Sagy N, Korenfeld N, Gal M, Goldstein I, Bar DZ 2026 · PNAS nexus | mechanism | mixed | low | Repeated fasting (and fasting-mimicking conditions in isolated hepatocytes) partially restored liver-unique DNA methylation patterns lost during aging/disease in a mouse/cell model, i.e. reduced epigenetic drift toward the pan-tissue methyl |
| van den Burg EL, Schoonakker MP, van Peet PG, van den Akker-van Marle EM, Lamb HJ, Longo VD, Numans ME, Pijl H 2024 · Diabetologia | RCT | tested-null | low | OFF-SCOPE (endpoint not measured): this IS a real 12-month FMD RCT (100 adults with T2D, monthly 5-day cycles), but its outcomes are glucose-lowering medication need, HbA1c and weight -- medication effect score -0.3, HbA1c -3.2 mmol/mol, weight -3.6 kg, glycaemic management improved in 53% vs 8%. It measures no biological-age endpoint, so it cannot support or null THIS claim. Belongs on claim-fmd-cycles-improve-cardiometabolic-biomarkers-in-humans; re-homed there 2026-10-04. |
| Lean ME, Leslie WS, Barnes AC, Brosnahan N, Thom G, McCombie L, Peters C, Zhyzhneuskaya S, Al-Mrabeh A, Hollingsworth KG, Rodrigues AM, Rehackova L, Adamson AJ, Sniehotta FF, Mathers JC, Ross HM, McIlvenna Y, Stefanetti R, Trenell M, Welsh P, Kean S, Ford I, McConnachie A, Sattar N, Taylor R 2018 · Lancet | RCT | tested-null | high | OFF-SCOPE on both axes: DiRECT neither administered an FMD nor measured biological age. Its endpoints are weight loss and diabetes remission. It was carried here as 'independent context', which is not an appraisal -- context belongs in the claim body, not in a row that votes. |
| Brandhorst S, Levine ME, Wei M, Shelehchi M, Morgan TE, Nayak KS, Dorff T, Hong K, Crimmins EM, Cohen P, Longo VD 2024 · Nat Commun | RCT | supports | low | Human Longo-lab secondary analysis: 3 FMD cycles associated with about 2.5-yr lower biological age on a validated clock, independent of weight loss; exploratory, small deep-analysis subsample (about n=15), single group. |
| Siavoshi F, Smith MD, Cassard S, Moreau GB, Brenton JN, Mowry EM, Fitzgerald KC, Bhargava P 2025 · Ann Neurol | RCT | mixed | moderate | RCT: FMD cycles reversed markers of accelerated biological aging. |
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