Ha - I so identify with that! An example...on Monday I went out for lunch and had a cheese sandwich and a few fries. Normally I would think ' Well, I've eaten cheese, bread and fries so I might as well write off the rest of the day now and stop off at Waitrose and pick up sone Kettle chips and a trifle. ' What I try very hard to do these days is think like a thin person... A naturally slim person would think ' that was a nice lunch. I'm full now and I won't eat again until I'm hungry...' and then they'd just get on with the day.
So I did this and had some Ryvita and fruit at about 6 ish when I started to feel a little peckish. Must admit, it feels weird to do that though.. battling against old, ingrained habits plus my tendency to eat compulsively. I've also been here twice before - lost a lot of weight and then back on it goes. This is the first time I have considered what it means to maintain though.
And re your 3 X 2 stone to go.. well, so did I last may, near as dammit. And trust me, if I can do it, anyone can. Application, vigilance at all times and make yourself the complete priority.