Fat adaptation means becoming efficient at burning fat rather than relying on glucose. Research by Volek shows it takes weeks to months: increased mitochondrial density, upregulated enzymes, improved ketone production. Once adapted, you experience stable energy, reduced hunger, easier fasting. Two paths: extended carbohydrate restriction or regular fasting — most combine both.
This companion covers the two fuel systems, physiological changes, timeline, how to get there, and signs of adaptation. (3 min read)