Acharya Mahaprajna
Bhagvan Mahavira talked more about fasting than he did about food. If food is our power, fasting has a tremendous power. We see that people who resort to Santhara (Undertake fast after giving up all attachments with a wish to die) give up taking food and water until there is life in them and they do it in such a state as though they have only 10 - 20 hours to live. They do it when some incurable disease has afflicted them. After undertaking such a fast, they continue to live for 10 - 20 days, with a feeling of being healthy.
The disappearance of their disease, their eyes regaining their lustre, recovery of their speech after having suffered loss of speech, the glow emanating from the body, etc. are found to be taking place during their period of fasting. This happens because the foreign substances accumulated start being thrown out of the body. The organs start having more strength to function to the extent that the foreign substances get ejected from the body. According to Physiology, it is believed that the lungs, heart and kidneys of a human being have the capacity to function effectively for three hundred years. Even today, these organs have the same capacity, but food becomes the chief cause leading to the depletion of that capacity.
