There are three basic rules in caring for a cat with kidney disease (CKD).
First, your cat must eat. CKD cats often have a poor appetite and that makes finding the proper diet difficult.
Second, the food must be low in phosphorus. Less than 0.55% phosphorus, on a dry matter basis, is a must. Dry matter means the analysis of the phosphorus content of the food has been determined once all the moisture has been removed from the test sample.
Third, current research has found that a high protein food will not cause CKD to progress any faster than a low protein food. The protein should be balanced with the fat (2-1 ratio) and it is best if the protein is hydrolyzed. Hydrolyzation of a protein makes that protein very easy to digest and process.
For more information read our paper on Kidney Disease in Cats.