Maybe you want to look at what you are eating? If you are eating a diet of lots of processed foods and foods that give you a quick rush/sugar boost then it may be that your blood sugars are rising quickly and then falling pretty quickly and is calling out for more sugar. If you think this is the case, try changing your diet and eating more fibrous foods (check out the Glycemic Index) and try eating foods that are low to medium. If this is the case, then you'll find that changing your diet will work. You may want to check with your doctor, though to rule out anything else.