Hi Linda, I'm not an expert by any means but with CKD it's usually the opposite, cats become really anorexic, it becomes a real challenge to get keep them eating. I wonder if the dietary change the Vet made was to drastic in protein restrictions? If a cat isn't getting enough protein they become ravenous...I've seen this first hand when one of mine was on a certain food that was supposed to be of high quality....even his coat color changed. Spent a lot of money on tests that all came back normal, so Vet suggested a new brand of food....he changed back to himself overnight almost
I know with CKD Vets suggest a lower protein diet, perhaps the one your feeding is just too low?
Talk to your Vet first but I would really try adding a small amount of another diet to the one he's on...one that list meat as the FIRST ingredient
Good luck dear boy we wish you all the best xoxo
Our Miss Teia is in early stage kidney failure, tried giving her subq fluids at home, but it stressed her too much. Will let her enjoy her remaining time as best she cane. Teia will be 18 on 21 December.
She has also had thyroid enzyme reading at the high end of normal for a few years.
She, too, likes Friskies canned, also add some Beechnut baby meat. She's doing okay.
My best wishes that your vet finds out what is going on with your cat, and can offer something to ease his condition.