Regardless of the reason for the switch, chances are you will need to transition your cat to a new food at some point in her life. When it’s time to make the change, try to take your time with your cat’s transition from one food to the next.

Cats have sensitive stomachs and may become ill or stop eating if their food is changed abruptly. This can happen when a new food alters the intestinal environment, which may lead to diarrhea, vomiting and a refusal to eat—that’s why it’s best to gradually wean your cat off the current food and onto the new one.

Our friends at Purina recommend using the “1/4 every 4 days” rule:

  • Add 25% new food every four days until your cat is completely transitioned to the new diet.
  • Start by feeding your cat 75% of her current food and 25% new food for the first four days.
  • On the fifth day switch to 50% current food and 50% new food for the next four days.
  • By day nine you should be feeding 25% “old” food and 75% new for the following four days.
  • In a little less than two weeks your cat will be fully transitioned to the new food!