I think your stomach send you signals that it wants food, but after a while it gives up. That's why hunger can pass, and you often get "too tired" to eat late at night. even more strange is- how come if you eat tons before going to bed, you wake up starving??!
I think maybe also your stomach shrinks to compensate if you are really hungry and then don't eat.
Its due to blood glucose levels. The extra insulin produced to deal with midnight snacks causes a dip in blood sugar in the morning, therefore causing hunger pangs. In contrast, if you go to bed hungry your body will not produce extra insulin overnight but will utilise your stored energy and morning blood sugar will be at a normal level.
me too beejay!!!! sometimes at 3 or 4 am if going to bed late and I cannot sleep cos im so hungry so i go and eat something substantial then sleep well afterwards.