beta-hydroxybutarate, a ketone, is the primary energy source while in a fasted state, and is analogous to glucose in use by organs. It directly provides energy

beta-hydroxybutarate, a ketone, is the primary energy source while in a fasted state, and is analogous to glucose in use by organs. It directly provides energy to the brain and the heart. Source: https://en.wikipedia.org/wiki/Beta-Hydroxybutyric_acid https://en.wikipedia.org/wiki/Beta-Hydroxybutyric_acid