# Ketosis

Ketosis is a fuel-switch in your body. When glucose runs low, your liver turns fat into ketone bodies. There are three: beta-hydroxybutyrate (BHB), acetoacetate, and acetone. These act as backup fuel for your brain, heart, and muscle. You reach ketosis through fasting, long exercise, or very-low-carb diets. In nutritional ketosis, your blood BHB rises above 0.5 mmol/L. That threshold comes from the work of Volek and Phinney. But BHB is more than fuel. It also works as a signal. It blocks certain gene-silencing enzymes (class I HDACs) and calms inflammation.

## Sources

- Newman JC, Verdin E. (2014). Ketone Bodies as Signaling Metabolites. Trends in Endocrinology & Metabolism. https://doi.org/10.1016/j.tem.2013.09.002
- Puchalska P, Crawford PA. (2017). Multi-Dimensional Roles of Ketone Bodies in Fuel Metabolism, Signaling, and Therapeutics. Cell Metabolism. https://doi.org/10.1016/j.cmet.2016.12.022

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_Canonical: https://longevity-switzerland.com/en/glossary/ketosis · Part of Longevity Cities · Updated 2026-06-22_