I would always rather watch an athlete hurl themselves across the stage with complete control over what their body is doing than a cadavernous shadow that looks like one more grande jeté may break them. Dance is a tough career path, why compromise the one tool you have? I'm glad the status quo of the emaciated ballerina has started to crumble in recent years, it can only be a good thing for the art form as a whole to promote well trained athletes at the forefront of modern ballet.
Misty Copeland is one of the best examples of the professional ballet world dropping it's bizarre and unhealthy conventions and starting to focus on celebrating both artistic talent and the sheer athleticism of the body in motion. Ballerinas have had a tendency to shy away from, if not actively avoid, building muscle for fear of deviating from the sylph-like expectation of their peers. Really, when you can perform and look like this?
I honestly think the quicker these outdated hang-ups on on body image are dropped the better for the development of the art form, for dancers' health and for the performances audiences go to see.
If you don't have the strength or fitness levels you can't expect to compete with those that do. You need to eat and you need to train. Get out of the studio - lift weights, go running, cross train with another sport. Do something - anything - that challenges your body. Stop caring about your body fat and your weight, train your body to perform and the rest takes care of itself. If you don't work your body it won't work for you.