I Brake dance and do Martial arts and I'm 5 5 I weigh 99 lbs so I don't think your under weight and like he said Muscal is Heavier then fat so you might just be gaining Muscal and losing fat thus keeping you at a Steady Weight I really don't think your under weight nice Picture but please just don't go anorexic and like I said to one of the other people you could try a liquid diet where you drink nothing but water for well I guess in your case 2/3 days a week for a while until you get to your Ideal weight as long as you keep dancing you should lose weight considerably fast Oh and take MultiVitamins it'll help your body Lose weight Faster and you'll be healthy. any Question just ask me or email me at Martialartsrules@hotmail.com