There have been reports over the centuries of people living for long periods without food, including stories about Christian saints like St Theresa of Avila, and of contemporary Indian holy men and women. Breatharians also claim to be able to live with little or no food for periods of years. These claims are, of course, dismissed both on grounds of common sense and because they contravene the assumption that living organisms obey standard laws of conservation of energy. But some scientific investigations of people who claim to live without food suggest that strange phenomena are indeed occurring.
For a discussion of this phenomenon in the context of energy conservation see Chapter 2 of Rupert Sheldrake's book Science Set Free/The Science Delusion. See also a documentary film In The Beginning There Was Light, a film by P.A Straubinger. See also the book Life From Light: Is It Possible To Live Without Food? A Scientist Reports on His Experiences by Michael Werner and Thomas Stoeckli.