Ahara (diet) Nidra (sleep) and Brahmacarya (abstinence) are recognized as the three Upasthambhas (sub pillars) essential for the smooth running of life. Among the three Upasthambhas, Ahara is considered as the best sustainer of life (Vrittikaranam Sreshtam).
The amount of food which without disturbing the equilibrium (of dhatus or doshas of the body) get digested as well as metabolized in proper time is to be regarded as the proper quantity. One should regularly take such articles which are conducive to the maintenance of good health and are capable of preventing the attacks of diseases.
The standard measurement of food for an individual is to be determined on the basis of one’s own digestive capacity. Ahara is categorized as Hitahara (wholesome) and Ahitahara (unwholesome). In a similar context, the terms Pathya and Apathya are also used to denote the acceptability and adoptability of a particular food in a given context.
Caraka mentions that the intake of incompatible diet is responsible for the causation of many diseases like sterility, blindness, visarpa (Herpes), udara (Ascites), insanity, fistula in ano, coma or fainting, intoxication, abdominal distention, stiffness in neck, varieties of anaemia, indigestions, various skin diseases, diseases of intestines, swelling, gastritis, fever, rhinitis, and infertility.