Staci, I don't know much about the special diets for thyroid problems out there. I do know a lot of people suffer from thyroid disease (including my Mom and Grandma) and it seems to be pretty well controlled in them with medication. I am not sure if the same meds are used in dogs as in people or not. I don't think you should let yourself be too worried though, I think you and the vet will be able to get it under control. It's great that she has already lost some weight! Good girl Keegie!