When I first started, I was hungry all of the time as well. I think it was withdrawls because my body was craving carbs and was not getting them. Now that I have looked back - I was eating probably over 300 carbs a day (fast food junkie). It took my body (and my mind) a while to get over it. My advice is that you eat when you are hungry - moderately, and when full, eat no more. I did, as many others do, pass a stage during my second week that it was hard to eat - no hunger whatsoever! When you hit this stage - keep eating - if you don't, you won't lose (info from my lessons learned!).
Mischa