When you said "burning muscle". Have you read the book "Protein Power?" He has a page in there that has four photos, all of the same guy. In the first he is a runner. Very emaciated looking with no muscle at all, in the second he has quit running and about a year or 2 later is VERY fat. In the third he has been lifting weights and the photo is taken about 6 months after the fat one. In the fourth he is no longer lifting weights as much, but he is still muscular.

The explanation about all the running and the inadequate diet using up all this guy's muscle made a lot of sense. He said that a lot of runners do this to themselves. They increase their metabolism, but don't actually build muscle. Since they don't they wind up in a catch-22 situation where they have to keep running just to maintain their weight. If they stop running they gain at an alarming rate. The solution is to build muscle through weight lifting, and adequate protein.

You might want to find a copy of it and at least read that chapter.