Owners should take note if their animals start getting picky over their cat food, experts have said.
Vet Dr Marty Becker and journalist Gina Spadafori write in the Sacramento Bee that a loss of appetite can be the sign of something more serious.
They say: "If the cat rejects a favourite treat, like a bit of roasted chicken, it's time to call your veterinarian. No one knows your cat better than you do, and if she suddenly rejects a food she has been willing to beg for all her life, you'll know your cat has troubles worth taking seriously."
The experts also suggest that if your animal loses weight, it may be worth asking a vet about pet medication that can help to stimulate its appetite.
According to Pets at Home, loss of appetite in cats can be the first sign of major illness but it notes that there are some occasions when cats refuse to eat.
These can include a change of ownership, a change of location, or just before a cat has kittens.