Maybe 'real hunger' is when our body's need for food is at such a point that this need over-rides all obtainable sense of subjective reality in perspective of priority to motive in physical, emotional, (spiritual? perhaps) and competely *pure* as can be, desire that one will become purely or truly, 'hungry'. i.e., if this need is not met, than one will not only feel like they'll die, but they actually will.
This experience should not be neccesary for most of us, and certainly has nothing to do with water fasting, or, not eating for a few weeks. Associating the two is nonsense.