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CAT / nutrition

When Should I Change My Cat's Diet?

Age or health concerns may mean it’s time for new food


Diet & life stage

Cats’ nutritional needs evolve as they age. Take protein as one example: Kittens need lots of it, but adult cats need less. In senior kitties, too much protein can harm the liver and kidneys.

Fortunately, there is food out there for each life stage. A kitten formula will have enough protein, fat and carbohydrates to satisfy the bright-eyed and bushy-tailed youngster, while adult and senior formulas have different balances of ingredients. Senior food, for example, may include supplements such as glucosamine and chondroitin, which help ease stiffness in an older cat’s joints.

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Diet and food sensitivities

If your cat has digestive troubles, breathing problems or itchy skin, a food sensitivity may be to blame. Cats can develop reactions to certain ingredients in their food — sometimes even after eating that ingredient for years with no problem. If the vet suspects that your cat has a food sensitivity, a diet switch is in order. Your vet may recommend trying novel proteins — a fancy way of saying “types of meat your cat has never tried.”

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Diet and wellness

Some foods are formulated to help cats get well or stay well. If your kitty has urinary problems, talk to your vet about urinary-health cat food.

After spaying or neutering, your cat’s hormones will change, which may affect energy, appetite and nutritional needs. Ask your vet if your cat should eat a spayed or neutered food formula after the surgery.

If your cat sometimes seems like a hairball factory, some food brands boast ingredients that help make coats healthier (and less likely to shed), plus dietary fiber to help digestion, keeping hairballs from forming. Look for an “anti-hairball” or “hairball-control” formula.

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Out with the old; in with the new

It’s best to change your pet’s diet gradually and systematically. A PetSmart store associate can help you find the life stage and lifestyle cat food your vet recommends.

  • Transition your cat to a new diet by substituting a little of the new stuff for the old in your pet’s usual meal. Swap out a little more at the next feeding, and so on, for seven days.
  • Avoid giving your cat any treats or human food for at least six weeks while you’re experimenting with a new diet.
  • It may take up to 12 weeks to tell whether a new diet regimen is working.
  • If your cat develops any new symptoms, talk to your veterinarian.

We recommend a seven-day switch:

  • Day 1: 75% old food, 25% new food
  • Day 2: 70% old food, 30% new food
  • Day 3: 60% old food, 40% new food
  • Day 4: 50% old food, 50% new food
  • Day 5: 40% old food, 60% new food
  • Day 6: 25% old food, 75% new food
  • Day 7: 100% new food