There is a chance your kitty simply doesn’t like the food given to them. It could be you’ve switched to a new type of food or a new food brand. It can even be your cat is bored of eating the same food or the food is spoiled.
A common symptom of many medical issues that a cat might experience is loss of appetite, resulting in a cat not eating as much. On the other hand, cats are masters of hiding pain, so a cat might seem “normal” in other ways.
So if your little furry friend has recently been vaccinated, the most probable cause of them not eating much is their body’s reaction to the vaccine! Temporary loss of appetite is a very common vaccination side-effect.