For most people, losing weight can be a lifelong struggle. There are many reasons for this. Sometimes people must take medication for another ailment or disease which causes an increase in hunger. Or the medication may affect the person's metabolism, slowing it down. These reasons can cause weight loss. Other people suffer from psychological problems with food that can make weight loss impossible without counseling. These people turn to food for comfort or to fill an emotional void. In this case, eating is just a substitute for something else. Food can never fill this void so the person continues to eat in the hopes of filling this unfulfilled void. Both of these situations can lead to weight gain and even to obesity.