Fasting — the deliberate, temporary abstention from food — appears across nearly every healing and spiritual tradition on earth, and modern biology is now mapping the mechanisms: autophagy, metabolic switching, hormonal recalibration, and reduction of systemic inflammation. The right approach depends entirely on the person: their health status, medications, history with food, and life demands. Fasting is a tool, not a virtue, and like any tool it can help or harm depending on how it is used.
Each step builds on the last.