Despite having been a total cycnic when I saw it at first, the Paul McKenna book and CD are fab.
4 principles:
Eat when you are hungry
Stop eating when you are full
Eat slowly
Eat things you enjoy
Sounds very simple, but it does take a bit of time to actually know when you are actually hungry and not thirsty, bored, or just in the habit of eating at a particular time.
The eating slowly helps your brain catch up with your stomach, and you end up eating smaller portions.
Eating the things you enjoy sounds dangerous, but if you chew a doughnut 20 times per bite, believe me, it tastes so greasy and stodgy, it's 'orrible. Eating fruit slowly, on the other hand, really brings out the flavour.
Basically it is just the same principle of eating less, exercising more, but it does give a bit of focus (and Amazon were selling it at £5 a while back - about the same as one week of WW/SW).