Ketone bodies are not just about energy. These metabolites are powerful signaling molecules that have profound effects on the proteome and protein quality control in the brain. Scientists, working in mouse models of Alzheimer's disease and aging, and in the nematode C. elegans, reveal the ketone body -hydroxybutyrate interacts directly with misfolded proteins, altering their solubility and structure so they can be cleared from the brain through the process of autophagy. The work hints at a tantalizing possibility -- ketone bodies as a global treatment to restore the integrity of the proteome, addressing one of the key hallmarks of aging.