Two theories:
Physical hunger and a body's inability to sense when it is full. I really believe there are some people out there who really can't sense when their stomachs are full and just keep on eating. It may be because the stomach is really enlarged/stretched out after many months/years of that kind of behavior. There are even folks who have undergone gastric bypass and lapband surgeries that then stretch out what should be a smaller pouch of a stomach by going back to binging behaviors. To deal with the physical fullness, never let yourself eat anything until you've had at least 16 oz of water and then measure out the portions of what you need to eat (not want to eat) to maintain or lose weight. Eat slowly and pay attention to the feeling of fullness--that feeling that tells you that your done and don't need more and then don't push past it. Stop eating. If the 16 oz of water doesn't help you to full, then try a fiber chew/tablet with the water prior to your meal. I was one who had difficulty feeling that "full" feeling prior to begining on the plan I'm on now. The fact that I cannot eat starches, sugars, or fats has helped with the "need" to continue eating. Protein and good, fresh veggies with a little fruit, eaten slowly really helps to give me that "full" feeling after drinking my water. If I feel full, even if my carefully measured portion of food is not gone, I stop eating.
Psychology hunger--a need to "fill" some achy spot inside of yourself that hasn't been filled through some other (emotion) means. This one is much tougher, I believe, to overcome. You need to discover "why" you need to fill yourself with food. There are many people out there who find it safer to hide behind the weight than to take a risk and lose it. What are they hiding from? For some it was years of mental or physical abuse by family or kids at school. For some, it's safer to be big is size and think this is why their last relationship ended, than to lose the weight and get out there and find companionship. I really think you need to do some soul searching to find out what you might be afraid of or what emotional need isn't being met to really stop the psychological hunger. My advice, from someone who teaches psychology/sociology at the high school level--and not from a psychologist--is when you feel that need to eat and keep on eating, instead, to write down what it is you're missing right then and there. Sooth yourself with a warm drink instead (cup of tea/coffee) followed by a big glass of water while you write down what is really hurting you. Afterward, if you really still want that food you were reaching for, have a taste, but not enough to satisfy the craving, or substitute something healthier instead. (Do you know that lean protein is rarely ever converted to fat in our bodies? Eat an ounce or two of protein instead of that sweet or salty crunchy thing you're craving. It will stop the binge from getting started.)
I hope this helps.
Laurie