Sometimes eating too much can be your way of coping with a certain situation or certain emotion.
Next time you eat too much take particular notice of how you are feeling at the time or what is going on at that time and see if you can figure out what it is that is maiing you want to eat so much.
Do this several times and see if you can find a pattern.
It can also be a way of filling a hole that you may be feeling in your life.