Echo that, try and think about how you are feeling as you go to eat and eat just enough to satisfy. The book suggests waiting for 20 minutes and then eating a bit more IF you are genuinly still hungry. If not hungry, it's only emotional eating/boredom/picking for the sake of it. I found it useful to get Paul McKenna's book and CD to listen to his ideas on 'I can make you thin'.
I have to confess I had the book for years and kept saying to my husband "I wish he'd hurry up and make me thin"
I struggle to know when I am full cos before I eat I am not hungry but when I stop I am but after halfan hour the feeling passes and I have learned (most the time) to let it pass