You should try a juice fast. I to was under weight but did try a juice fast with suppot of my doctor, who is a DO. I did loose 5 pounds the first week but I kept at it and kept working out, I had more energy and felt great and what do you know I put on 15 pounds in 23 days, drinking juice! I am at a much healthier weight and have changed my eating habbits. I try hard to stay away from refined sugars and am trying to eat more naturally. It's a never ending battle. I did get a little sick but my doctor said I would because of toxins re-entering my body. I am so glad I fasted. It was the best thing I have ever done.