Most of us have felt the urge, the unstoppable craving driving us to seek out something sweet and devour it in a flash. That uncontrollable yen for cookies, cake or ice cream or that whole basket of bread calling to us to finish it off. Why do you overeat? Why does that cookie have such power over you, even though you know it will make you fat and sick? Is it an indication of your moral weakness, lack of will power, or is it a powerful hardwired brain response over which you have little control?