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Journal ArticleNature communications·Jul 2026

A Little Body Fat in Old Age May Actually Help You Live Longer

Key Insight

This is early worm research, so no human takeaway on citrulline or fat exists yet.


Scientists found that a small amount of fat buildup during aging helped worms live longer, not shorter. The driver was citrulline, a compound made in the body that switches on fat storage. Worms low in citrulline stored less fat and died sooner, and adding it back reversed that. This challenges the idea that all fat gain with age is bad, but it was only shown in worms.

Conflict of Interest Disclosure: The authors declare no competing interests.

Disclaimer: Research summaries are provided for informational purposes only and do not constitute medical advice. Always consult a qualified healthcare professional before making changes to your health routine.