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

*Citrulline drives age-related lipid deposition for healthspan.*

- **Evidence Level**: Preliminary
- **Publication Types**: Journal Article
- **Journal**: Nature communications
- **Sample Size**: C. elegans (roundworms)
- **Authors**: Li C, Wang Y, Xu X, Li C, Zeng Z, Tan J, Fu L, He Y, Liang Y, Zhang Q, Liu J, Zou X, Zhang J, Liang B
- **Published**: 2026-07-14
- **Topics**: metabolism, lipids, citrulline
- **DOI**: https://doi.org/10.1038/s41467-026-75498-4
- **Original Source**: https://pubmed.ncbi.nlm.nih.gov/42448700/

## Summary

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.

## Practical Takeaway

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

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_Canonical: https://longevity-switzerland.com/en/research/a-little-body-fat-in-old-age-may-actually-help-you-live-longer · Part of Longevity Cities · Updated 2026-07-14_