When you have a lot of weight to reduce then the value of reducing the weight is very high, it is usually so high that you value reducing the weight more than you value the emotional benefit of eating.
Therefore when you have reduced some of the weight then you don't need it as much, therefore suddenly the value of reducing weight and the value of the benefit match each other, this tends to be a balance point and why people say they can get to a certain weight but then seem to lose the will to finish the job off.
Therefore you need to look at the strategies you are running, it is a mind read but if you are running an away from strategy i.e. I don't want to be big anymore then you tend to find that finishing the job off can be less easy.
If though you run a towards strategy i.e. I will be slim then the closer you get then the more the wind is behind you.
Mike