If your adolescent cat eats food meant for kittens, will you end up with a fat cat? And when is the right time to let senior cat food out of the bag?

These are just a few questions you must grapple with now that major pet food manufacturers offer kitten chow, adult food and even a geriatric diet, formulated for different stages of your cat’s life. The pet food industry also manufactures foods for cats with different ailments, from obesity to allergies.

“In the old days, we just basically fed our cats one diet. You started them on a food and kept going for the rest of their lives,” says Bonnie Beaver, DVM, a professor at the Texas A&M University Veterinary College. “They did OK, but now they can do even better.”

From Kitten Food to Adult Food
Pet food manufacturers have invested considerable time, research and money in developing foods that fulfill your cat’s particular nutritional needs during each life stage. “Growing kittens have bones that are actively expanding,” says Dr. Beaver. “Their needs in developing their nervous system are also different than they are for an adult cat.” As a result, kitten foods often contain extra calcium for bone development, fat to aid growth, and important vitamins and minerals.

Pet nutrition experts say the best time to transition your pet from kitten food to adult cat food is somewhere between 9 and 12 months of age. Dr. Beaver explains that most cats’ bones stop growing when the feline is around 14 months of age, with about three-fourths of that growth completed at 9 months.

Other factors that should influence your decision about when to transition your furry friend to a new diet include:

  • Neutering Spaying or castrating your cat will influence its daily energy requirement. “The decrease in circulating estrogens or androgens will lower the daily energy requirement of a pet compared to when it is not neutered,” says Korinn Saker, DVM, director of the Nutrition Service at North Carolina State’s Veterinary Teaching Hospital. Work with your veterinarian to establish the appropriate amount of food to meet your cat’s energy needs — without going overboard.
  • Breed There may be some slight differences based on breed. Larger breeds, such as Maine coons, may be on kitten food a bit longer based on their anticipated adult body frame size.

From Adult to Geriatric Diet
An adult cat’s energy levels usually decrease over time. “Geriatric animals don’t need as much fat in the diet, and you need to be careful that they can digest the kinds of protein in their diet,” Dr. Beaver says. “Plus, their kidneys are also notorious for giving out as they get older.”

Pet nutrition experts say the time to transition your cat from adult food to senior food starts as early as 7 years and can go as late as 10 years. But not all pets will age at the “textbook” time. Keep these two factors in mind:

  • Activity level If your cat continues to be very active and shows no signs of slowing down by age 7, you may want to consult your veterinarian about keeping your pet on adult maintenance food for longer. “I’ve certainly known cats that live until they’re 20 years old,” Dr. Beaver says. “They may not be geriatric until they are 10, but other cats can age more fast.”
  • General health Annual checkups for your pet are a must. During those appointments, your vet will draw blood and run tests to detect whether your cat is developing diabetes or other diseases. Your veterinarian may then recommend switching your pet to a senior diet.

Help Your Cat Transition Between Foods
The two biggest risks of transitioning your kitten or cat to a new life-stage diet are that your pet will reject the food or develop gastrointestinal problems. These steps can help prevent these problems from happening:

  • Go slowly Cats seem to be more sensitive to dietary alterations than dogs, particularly if they are ill. Dr. Saker recommends transitioning your cat to a new diet over a 7- to 10-day period.
  • Mix new food with old Cats are also notoriously finicky eaters. One way to avoid having your cat reject a new diet is to gradually mix new food with the old until you finish off the old food. This is easier on your cat’s GI system and palate.
  • Provide plenty of drinking water Cats typically don’t drink very much, and that can cause problems — particularly if they’re eating only dry foods.
  • Get them used to a mix of foods Dr. Beaver recommends that during kittenhood, you introduce your cat to a mix of different flavored dry and wet foods. This will lessen the likelihood of rejection later on.

Life-stage foods are no gimmick. These foods have been formulated based on many years of research to meet your pet’s changing needs at different points in their lives. “As these nutritional needs change,” Dr. Saker says, “the diet should change.”