Fasting should be chiefly mental. Mere abstinence from food will do no good, it will even upset the mind. Spiritual unfoldment will come rather by regulating eating. What is the purpose of fasting? When fasting, one’s senses become subdued. Then the mind becomes non vacillating. The most important thing is to control the mind. Where is the mind? Where is the body? Where is the Jiva? It is all in the self. Food does not make up one’s thoughts. The very fasting of determinations, doubts and thoughts alone would control the mind. If one understands the self all food controls are unnecessary. – Ramana Maharshi