[anonymously]

All processed foods contain by-products. Kibble and canned dog food are processed foods. There is nothing wrong with Royal Canin
I would listen to your veterinarian, see if she (your dog) stabilizes, at least give it a few months. If not, I would consult a Internal Medicine Specialist.

Some info you may find helpful at this site: http://skeptvet.com/Blog/category/nutrition/