You’ll notice some age-related changes when your cat is about seven to twelve years of age. You can start feeding your cat on a senior diet.
A diet with lower caloric density to avoid weight gain is a start, but with a normal protein level to help maintain muscle mass. Also talk to your vet about increasing your senior cat’s vitamin E intake. Antibody response decreases as cats age. That’s why you need to feed it vitamin E if it is actually older than seven. It will have an antibody level that’s as strong as a younger cat. Any cat can get old. All it has to do is to live long enough in a healthy way.