"Food is the chief of all material things. It is the medicine for all kinds of disease. From food all things are born"

Taittriya Upanishad

One must eat in measure, and the measure of food is determined by the strength of one's gastric fire. A proper measure of food is that which is well digested in the appropriate time. According to the Gheranda Samhita, at the beginning of Hatha Yoga practice one should refrain from eating excessively acid, bitter, salty or pungent foods. the same text gives good advice about quantity, advising that "half the stomach should be filled with food, one quarter with water or other liquid, and one quarter should be kept empty to aid the practice of breath control.

The daily diet should be made up of food that not only helps to maintain well being but also serves as a prophylactic against disease. From the moment of conception some people are equibalanced as regards the proportion of elemental principles in the body; others have a predominance of one element or another. The person who has an inner physical balance alone enjoys perfect health, while all others are ever liable to disease.Charaka Samhita