Breakthrough...

This seems so silly, but I had a kind of diet breakthrough that is so obvious...
Although I do find dieting very difficult (understatement of the decade!), what is harder in some ways is maintaining the goal weight when I reach it. I get to a point where I am so utterly terrified of putting weight back on that I still diet until I break... and that breaking point is when I suddenly stop caring about food as fuel and start eating normally. Bearing in mind that 'normal' for me has always been - eat until I'm almost sick and/or can't even get up, have whatever is in front of me, gorge, stuff, eat unneccessarily when not hungry, have at least five treats a day (a treat being 1000+ calories of fatty, sugary stodge), chocolate and crisps are one of my five-a-day.... see the problem? lol
I admit that I am an extreme dieter - which is why I can lose 4lbs a week with little or no exercise - but when I reach my goal weight this time, I am going on another diet. Yes... another diet. A maintaining diet. I know that at approximately 10 stone in weight (140 pounds) I need to eat round about 1500 calories a day to maintain that weight (with little or no exercise) and about 1200 calories to lose one pound a week.
So I am trying to memorise calories... and I always round it up to the nearest 50... and I'm getting pretty good at remembering all those numbers :) I want to get to the stage where it's natural for me to stop eating when I reach a certain amount of calories in a day... or if I go over, to even out the rest of the week so that I maintain my weight.
I cannot believe that I couldn't figure this easy and obvious strategy out before now. Of course... putting it to the test when I reach that magical 134 pounds will see how well this works out :)