It violates the laws of physics. It is impossible. He would be a human perpetual motion machine. If it exists, then our universe does not.
To answer your reply with the best that I have would take more time than I have now.
A lady wants to meet me at a karaoke club, so I am gone!
The idea is that the yogis can draw energy from the spiritual universes and thus can learn to live without taking energy from this particular material universe. I suppose an atheist would call it impossible, but a Christian should understand the concept, even if he is likely to condemn the yogi's energy sources as demonic because he doesn't really believe God would ever do that for him. :)