The problem of overeating is directly related with stress level of the body. When we start to worry about something, the body begins to develop certain hormones, which creates an instant urge in us to eat something. This hunger is a temporary phase and if you do not eat anything for sometime, and just wait and watch your hunger, you will discover that after 10 to 15 minutes, you wont feel hungry anymore. The reason for it is that you were not really hungry at that point! It's the stress that created an illusion of hunger and had you trapped in that illusion, you'd have had ended up eating some junk food to satisfy that 'illusionary hunger'!
Now if you a live a life, which is full of stress and / or worry a lot about different things, then you can easily understand how many times you ended up eating a big pizza or a couple of burgers, when there was no need for them at the first place! A simple way to know if your hunger is a genuine one is to wait and watch it for 15 minutes. If it stays after that time, it's a real one, and if you feel that your urge to eat is constantly decreasing during that time, then you can conclude that it was created because of the 'stress hormones'.
A great ancient Indian medical guru 'Charak' said that 90 percent of all of health problems are due to stress. This is also true for most of the people who have overweight problem. If you fill a glass of water and continue pouring water in it even when its completely full, water will start flowing outside it, and the same concept applications for human body as well. If you overeat, then that extra food will start showing itself as fats! So, its very important to prevent overeating, and by reducing your stress level, and developing an understanding towards real and illusionary hunger, you can make it possible.