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The Study

Effect of long-term caloric restriction on DNA methylation measures of biological aging in healthy adults from the CALERIE trial

In simple terms

This study found that eating fewer calories for two years slightly slowed a special molecular clock that tracks how fast your body is aging. But it didn't prove that people live longer or get sick less — just that one tiny sign of aging changed a little bit.

65%

Analysis score

65/ 90

Maximum 90 for a randomized controlled trial.

Where the score came from

Reporting0
Methodology73
Publication100
Statistical77
Study type (basis of the score)
Randomized Controlled Trial
Level 1b - Individual RCT
What’s the bottom line?

Scientists tested if eating 25% fewer calories for 2 years makes your body age slower, using a special blood test that tracks how fast you're aging.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Randomized Trials
Level 1b
65

65 / 100

Quality score

Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.

Can establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1Even a small 2–3% slowdown in aging could mean people live healthier longer — similar to the benefit of quitting smoking.
  2. 2People who ate fewer calories aged 2–3% slower on the DunedinPACE test, but their overall 'biological age' didn't change on other tests.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

Nature aging

Year

2023

Authors

Waziry R, Ryan Cp, Corcoran Dl, Huffman Km, Kobor Ms, K. M, Graf Gh, Kraus Vb, Krauss We, Lin Dts, Pieper Cf, Ramaker Me, Bhapkar M, D. Sk, Ferrucci L, Hastings Wj, Kebbe M, Parker Dc, Racette Sb, Shalev I, Schilling B, Belsky Dw

Open Access
150 citations
Analysis v5
Fit Body Science verdict — we translate health studies into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.