What are the nutritional requirements of my senior cat?
As cats age, their energy needs stay basically the same throughout adulthood. If your cat has a health concern, consult with your veterinarian regarding the appropriate diet. Do not change your cat's diet without consulting your veterinarian.
Some studies have shown that senior cats do not digest food as well as younger cats, and thus absorb less fat. This means that older cats may actually need to consume more fat to get the same amount of energy. You'll need to monitor the weight and body condition of your cat, and adjust his food amount accordingly.
Your cat's protein needs are higher than the protein needs of many other animals. Again, many senior cats may not be able to digest protein as well as they did when they were younger, and their protein requirements may actually be higher. Unless your cat has a health condition which calls for protein restriction, your senior cat should NOT be placed on a protein restricted diet.