This article examines the physiology of fasting, the scientific basis of India's lunar-calendar fasting tradition, and the convergences between ancient practice and modern biology. The article covers: the hour-by-hour fasting physiological timeline (insulin-glucagon dynamics, glycogen depletion, ketosis, AMPK activation, mTOR suppression); autophagy as the primary cellular mechanism of fasting's health benefits (2016 Nobel Prize, Yoshinori Ohsumi; ULK1, Beclin-1, ATG proteins; 16-24 hour initiation, 24-72 hour peak zone); the specific fasting occasions of the Indian lunar calendar (Ekadashi twice monthly, Purnima, Amavasya, Mahashivaratri, Pradosh, Navratri); the scientific evidence for lunar biological effects (Cajochen et al. 2013 Current Biology — 30% decrease in deep sleep, 20 minutes less total sleep, diminished melatonin around full moon, measured under strictly controlled conditions; 2025 TPM integrative review); the specific geometry of Ekadashi's lunar position (120-132° waxing, 300-312° waning) and its proposed physiological effects; and the Ayurvedic rationale for lunar-timed fasting through the concepts of Ama accumulation, digestive system rest, and circalunar biological alignment. The governing argument: India's lunar fasting calendar is one of the most sophisticated biological maintenance programmes ever developed by any civilisation. Its efficacy rests on the solid science of fasting itself, enhanced by cultural scaffolding that makes twice-monthly 24-36 hour fasts sustainable across generations, with additional layers of evidence suggesting the specific lunar timing may amplify the benefits through genuine circalunar biological mechanisms that modern research is only beginning to document.
Narayan Rout (Fri,) studied this question.