Our 20-year-old has CKD and we feed him a prescription food in the morning (Royal Canin Renal Support D) and a non-prescription food in the evening (Forza10 Renal Support paté).
Treats are limited to catnip, cat grass, and the very rare small piece of plain chicken.
What do you feed yours?
He is so food motivated that his treats are just more of his usual prescription food, but stored in a different container than his regular food is given from.