One very common reason I find people over eat is because they are what's termed as an 'emotional eater'.
Have you ever found yourself eating more than you need to and feeling over full because you're feeling; bored, upset, stressed, depressed, angry, nervous or even happy and in a celebratory mood?
Whatever the emotion is that triggers this overeating response you need to be very aware and conscious of and modify and control your eating habits at this time.
When you find yourself reaching for the tub of ice cream or whatever you emotional food of choice is, reach for a healthy option instead like raw beans or fresh carrots. Better yet don't use food at all to mask the emotion trying to make yourself feel better.
Instead address the emotion and examine why it's happening and talk it through with someone. If you can't, get yourself away from the environment where there is the temptation to eat and most importantly away from the environment (or person) that triggers the emotional response in you.
After all...the only person you're harming buy 'emotional eating' is you.