Actually, in pre-conditioning, just eat until you're satisfied at meals. You don't have to measure or weigh, if I remember correctly. It is a long time between meals and you just have to hoooollllddd oooonnnn!
It will get better, I promise. Right now, you're sort of detoxing from carbs. They tend to make you feel immediately full. Believe me when I say that your body will thank you for this, but right now, it's stomping it's foot and pitching a fit! Good luck!