Hindu scriptural works declare that there is a close relationship between the body and the mind. In fact it is the mind, as the repository of karma, that creates the future body since it survives the death of the physical bodies till the attainment of mokṣa (liberation). Hence the body and the mind act and react on each other. In this context āhāra or food assumes great importance. The quality of food affects the quality of mind. In fact the Chāndogya Upaniṣad (7.26.2) goes to the extent of declaring that purity of food leads to purity of mind which results in the excellent retention in memory of all that is heard and studied from the preceptor. The resultant wisdom leads to freedom from all bonds. This is because the subtle part of the food that is eaten sustains the mind whereas the gross part of it nourishes the body.
Āhāra is classified into three groups:
sāttvika, rājasika and tāmasika (vide Bhagavadgītā 17.7-10). Sāttvika food contributes to longevity, health, strength and happiness. Rājasika food generates passion leading to sorrow and suffering. Tāmasika food produces dullness, indolence and drownsiness.
The various scriptural works mention long lists of food articles coming under these three categories.
There are regulations with regard to the quantity of food to be eaten and elaborate rules regarding the time, place and also company in which it should be taken.
Moderation in eating is always the rule. Hindu medical works recommend that half the stomach should be filled with solid food and a quarter with water leaving the rest of the space for the movement of air.
One is advised to avoid partaking of food before performing spiritual practices. Solar and lunar eclipses are believed to have very adverse effects on food and hence one should not eat during eclipses.
Places to be avoided for eating include temples, public places, moving animals and vehicles.
Impurity (doṣa) can accrue to food on three counts: jātidoṣa, nimittadoṣa and āśrayadoṣa. Garlic or cabbage for instance, is impure by its very species (jāti) and hence must be avoided. Nimittadoṣa comes by external impurities like dust or hair as also an insanitary handling of food. This can be obviated by strictly observing the rules of health and sanitation. Foods cooked, touched or handled by persons of questionable character become contaminated by their evil psychic vibrations which can be transmitted to those who consume them. This type of impurity is called āśrayadoṣa, doṣa or defect arising as a result of āśraya or repository. Offering the food to God before eating destroys this impurity.