Hi my name is michaela. I m 15 years old. According to all my doctors I m underweight . I m 5 5ish and I weigh 91 pounds. For the past year I have been trying to gain weight (fat) by eating more calories but in healthy foods . Well it hasn t really been working. I thought that what if I try to gain the weight in muscles? Like exercising a ton and eating healthy. The only thig I m worried about is what if it makes me loose more weight! Is it a good idea? Any suggestions? Thanks so much!