Special desire to eat may be caused by the following reasons: 1, bulimia, some patients with bulimia nervosa always have no reason to overeat, and always eat a lot of things, after eating the mood is more comfortable, do not eat will be anxious, irritable and restless, but also after eating there will be a certain sense of regret, when overeating after the vomiting or diarrhea behavior. 2, may be encountered frustration The problem of stress leads to sudden overeating, want to eat, with such behavior to relieve the inner anxiety, depression and other negative emotional problems, because eating itself can bring joy, happiness and quiet mood, especially the appetite for satisfaction in line with the lower physiological desires, food and sex, which is the human instinct and nature, so it is possible to eat to relieve the problems encountered. 3, May be caused by physical disease, such as hyperthyroidism or diabetes and other diseases may appear overeating, drinking and eating more than the problem.