Cats are often very fussy feeders, but if a cat suddenly loses its appetite you should be concerned and not simply ignore it as plain fussiness.
Firstly you would need to rule out any kind of medical or physiological problems that could be associated with lack of appetite so a trip to your veterinarian for a full check up is indicated. It could be something as simple as a rotten tooth or some other easily remedied problem – however in some cases it could well be a symptom of a very serious problem, so your veterinarian’s expertise is necessary.
When cats refuse food for any period of time it can be very dangerous as stored fat is used for fuel. This is processed by the cat’s liver and a protein intake is vital. Losing fat reserves puts the liver under a lot of pressure and could result in liver failure and even death in some cases. So as a first line of treatment any medical issue must be ruled out!
Behaviour that causes lack of appetite
Have you recently moved house? Is there a new baby in the home? Have you recently acquired a new pet? All of the above can cause a cat to suffer stress which could result in a lack of normal appetite.
Cats are pretty sensitive animals and any sudden change in the environment and or the home (a bereavement or divorce or owner based trauma) can have a huge effect on an individual’s coping mechanism. In most cases cats do adjust pretty quickly. Try obtaining a cat pheromone diffuser or spray to help the cat feel safer, and make sure that any obvious stress in the environment is reduced as much as possible whilst the cat is making the adjustment to the changes in the home etc.
Travel can also affect a cat’s appetite – car or plane travel could cause motion sickness, which could be another cause of not wanting to eat for a while. However in this case the appetite should improve within a day or so.
In a small amount of cats, it has been noted that a few cats do react negatively to their yearly inoculations, with a lack of appetite being one of the most common side effects. However this is not a valid reason to avoid giving these life saving inoculations. And usually if this is the cause the side effects are mild and temporary. If you are in doubt – consult with your veterinarian.
If you have ruled out any possible physical or stress related cause then it is possible that your cat is simply a fussy eater. Any feed change can take a while for most cats to get used to so something as simple as a change in brand could well be the cause! A good tip is to add a tiny bit at a time of the new feed, mixed with the bulk of the feed that will be eventually phased out. It is also fine to mix some high value extras in the feed for a while just to get the cat started. But again if you are in any doubt consult with your veterinarian.