In non-obese adults, reducing calorie intake for two years does not change biological age as measured by PhenoAge or GrimAge DNA methylation clocks.
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Two years of caloric restriction does not significantly alter biological age as measured by PhenoAge or GrimAge DNA methylation clocks in non-obese adults.
Very strong evidence
Randomized trialsOne good-quality study supports this claim.
What the research says
1 study reviewedSupporting (1)
Randomized Controlled TrialHuman
Eating 25% fewer calories for two years didn’t change two common aging markers (PhenoAge and GrimAge), which means calorie cutting doesn’t affect all ways we measure aging — it only changes some, not all.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
Eating fewer calories changes how chemical tags attach to DNA in specific locations linked to aging. These changes affect some aging clocks but not others, because each clock tracks different sets of DNA marks tied to distinct biological processes.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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In non-obese adults, reducing calorie intake for two years does not change biological age as measured by PhenoAge or GrimAge DNA methylation clocks.
Mechanism
1 studyEating fewer calories changes specific chemical marks on DNA that track how fast the body ages, but only for some of those markers. Other aging markers stay the same because they measure different biological processes that aren't affected by reduced calorie intake.
Eating fewer calories changes how chemical tags attach to DNA in specific locations linked to aging. These changes affect some aging clocks but not others, because each clock tracks different sets of DNA marks tied to distinct biological processes.
Reduced energy intake alters activity of nutrient-sensing pathways including mTOR, AMPK, and sirtuins, which regulate cellular metabolism and stress responses
Altered nutrient-sensing signaling modifies the activity of DNA methyltransferases and demethylases, leading to site-specific changes in DNA methylation patterns at CpG sites
These methylation changes occur preferentially at CpG sites that are part of the DunedinPACE epigenetic clock, which captures the pace of physiological decline through methylation linked to cellular maintenance and inflammation
The same methylation changes do not occur at CpG sites that constitute the PhenoAge and GrimAge clocks, which are anchored to different biological processes including plasma protein levels and immune senescence
The differential methylation response results in a measurable slowing of the DunedinPACE clock while leaving PhenoAge and GrimAge unchanged
Evidence from Studies
Supporting (1)
Community contributions welcome
EFFECT OF LONG-TERM CALORIC RESTRICTION ON THE PACE OF BIOLOGICAL AGING IN HEALTHY ADULTS FROM THE CALERIE TRIAL
Eating 25% fewer calories for two years didn’t change two common aging markers (PhenoAge and GrimAge), which means calorie cutting doesn’t affect all ways we measure aging — it only changes some, not all.
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review of Long-Term Caloric Restriction Effects on PhenoAge and GrimAge in Non-Obese Humans
Population: Non-obese adults; Intervention: Caloric restriction for two years; Comparator: Ad libitum diet; Outcome: Change in PhenoAge and GrimAge DNA methylation clocks; Duration: Two years
Double-Blind Randomized Controlled Trial of Two-Year Caloric Restriction vs. Control on Epigenetic Aging in Non-Obese Adults
Population: Non-obese adults; Intervention: 20-25% caloric restriction for two years; Comparator: Ad libitum diet; Outcome: Change in PhenoAge and GrimAge DNA methylation clocks; Duration: Two years
Prospective Cohort Study of Caloric Intake and Epigenetic Aging Trajectories in Non-Obese Adults Over Two Years
Population: Non-obese adults; Intervention: Natural variation in caloric intake; Comparator: Higher vs. lower caloric intake groups; Outcome: Change in PhenoAge and GrimAge DNA methylation clocks; Duration: Two years
Cross-Sectional Analysis of Caloric Intake and PhenoAge/GrimAge in Non-Obese Adults at a Single Time Point
Population: Non-obese adults; Intervention: Self-reported long-term caloric restriction; Comparator: Non-restricted group; Outcome: PhenoAge and GrimAge at one time point; Duration: Single time point
In Vitro Analysis of Caloric Restriction Mimetics on DNA Methylation Patterns in Human Fibroblasts
Population: Human fibroblasts; Intervention: Low-glucose or serum-deprived media mimicking caloric restriction; Comparator: Normal nutrient conditions; Outcome: Methylation changes at PhenoAge and GrimAge CpG sites; Duration: 7–28 days