Plants are breatharians... Plants may get nutrients from the ground, but all thier energy is from the sun, and from the air. Supposedly all life on this planet comes from plants... so I think it is very possible that people do not need food to live. But I do think that if this is the case, they probably still need water and nutrients of some sort. Unless they get that from the air...
Its interesting because supposedly like 50-90% of our energy goes into digesting food.... so if a person could get energy without using digestion... they wouldnt need all that much. Imagine that... if a person could just absorb all the energy they need through thier skin, or lungs. And then just absorb nutrients they need through thier skin and lungs. Maybe even IV... kinda like when some one is in a coma.