Prahlad Jani, 82, had shown no signs of ill effects after six days under observation without food or water, The Daily Telegraph reported Thursday.
Jani said he is a "breatharian" living on a "spiritual life-force" given to him by a goddess, the British newspaper said.
Scientists said they may be able to learn from Jani's physiology.
"If his claims are verified, it will be a breakthrough in medical science," said Dr. G. Ilavazhagan, director of the Defense Institute of Physiology & Allied Sciences. "We will be able to help save human lives during natural disasters, high altitude, sea journeys, and other natural and human extremities. We can educate people about the survival techniques in adverse conditions with little food and water or nothing at all."