Like everything else in life, we need to be able to separate what we WANT and what we NEED. It's hard with food, because we've relied on it for emotional support instead of just physical sustenance. The WANT is driven from the desire (physical, even) for endorphins and norepinephrine and dopamine release from the brain. It is the same as what happens for drug addiction, including sugar addiction. The pleasure centers of the brain get tickled when we endulge in the addictive substance and creates a desire for more. It just feels so darn good to eat! (All for about 5 minutes!)
The real key is to retrain the brain to feel pleasure with healthy options like exercise, gardening, music, meditation, or eating a beautiful, delicious vegetable. It can be done, but just takes repetition. This is what the "Honeymoon" stage of weight loss surgery is all about - using this time to learn new strategies and retrain the brain. The time comes for all of us that we get more hungry, but without the feeling of restriction. This is where folks start to regain.