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 leans-support: real but preliminary, and to be read with the commercial-interest caveat in mind.
📅 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
The evidence (5)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Shtark RB et al 2026 · study_type: animal | 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 Trigt 2024 · Br J Gen Pract | RCT | tested-null | low | Primary-care RCT: an FMD programme improved cardiometabolic and aging-related markers. |
| Lean 2018 · Lancet | RCT | tested-null | high | Independent context: large diet RCTs demonstrate hard-endpoint change (diabetes remission) — the FMD claim rests on a soft surrogate (aging clock) not yet linked to morbidity/mortality outcomes in FMD trials. |
| Brandhorst 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 2025 · Ann Neurol | RCT | mixed | moderate | RCT: FMD cycles reversed markers of accelerated biological aging. |
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