Life in Ayurveda is conceived as the union of body, senses, mind and soul. The living man is a conglomeration of three humors (Vata, Pitta &Kapha), seven basic tissues (Rasa, Rakta, Mansa, Meda, Asthi, Majja & Shukra) and the waste products of the body i.e. mala, mutra and sweda. Thus the total body matrix comprises of the humors, the tissues and the waste products of the body. The growth and decay of this body matrix and its constituents revolve around food which gets processed into humors, tissues and wastes. Ingestion, digestion, absorption, assimilation and metabolism of food have an interplay in health and disease which are significantly affected by psychological mechanisms as well as by bio- fire (Agni).