I feel the need to reply.
Although there are many reported cases of holy men in India living of nothing, prayer, sunlight or other etherial substances, it is important to realize that (not counting all the fakes) these men still drink water.
Water in the western world is considered a drink with no nutrient content, the story is quite different for primitive India.
Many of such holy men drink from the river Ganghes or other sacret rivers. Taking the river Ganghes as example, it is absolutely loaded with nutrients from varied sources, such as the remains of partly cremated corpses that are thrown in the Ganghes as part of funerals, the excrements of people relieving themselves in the river, the food remains of washed out pans and various other sources.
This water would not become someone who wasnt used to it very well, but if you are used to bad conditions and accept greater health-risk, you might very well be able to live of the water, especially if your primary activity exists out of sitting on a rock meditating.
Agreed. The Ghanges is IMO the equivilant of drinking from a restaurants wash basin witextra fecal matter thrown in.