Chronobiological Foundations in Classical Ayurveda: Bridging Kala-Bhojana, Dinacharya, Ritucharya, and Vega Vidhi With Molecular Epigenetics and Circadian Biology

Contemporary preventive care faces challenges from lifestyle-related disorders, metabolic syndromes, and stress-linked psychiatric conditions. Many of these issues stem from circadian misalignment and elevated allostatic load. Millennia before the discovery of transcription-translation loops, classical Ayurvedic texts (Charaka Samhita, Sushruta Samhita, and Ashtanga Hridaya) formulated an advanced chronobiological framework based on Dinacharya (daily routines), Ritucharya (seasonal routines), Kala-Bhojana Siddhanta (chrononutrition), and Vega Vidhi (impulse regulation). This paper provides an original, independent critical analysis bridging these classical frameworks with modern molecular biology and chronobiology. Specifically, we examine. Kala-Bhojana Siddhanta alongside contemporary time-restricted feeding, focusing on peripheral metabolicentrainment, AMP-activated protein kinase pathways, and sirtuin regulation. • The mechanistic connections linking Dinacharya and Ritucharya to epigenetic modifications—exploring how behavioral entrainment regulates DNA methylation, histone acetylation, and non-coding RNA expression to support immunity and cellular proteostasis.• The neurobiological and autonomic consequences of Vega Dharana (suppression of somatic urges) versus Dharaniya Vega (restraint of destructive psychological impulses), with a focus on autonomic balance, visceral signaling, and limbic regulation. By synthesizing classical Sanskrit science with modern empirical chronobiology, this review outlines an integrated, personalized framework for lifestyle medicine.