Cats are highly intolerant of mouth pain. Dental or oral problems including bad teeth, gum disease, sore tongue, wounds inside the mouth or mouth ulcers make it hard to eat and can completely stop a cat from eating. Sometimes the mouth pain may make it difficult to eat certain types of food, but the cat still eats very soft food, giving the impression of finicky habits. If your has groomed contaminants from its fur it may have burnt its mouth or throat - it needs urgent medical treatment as it may also have ingested poison. Sometimes a cat requires tube feeding while the mouth heals.
Throat infections can make it uncomfortable for the cat to swallow.
Stress can also upset feline appetites. The temperature of the food . Most cats don't like food which is too cold. Serve food at room temperature or warm it slightly to mimic the temperature of fresh caught prey. The food bowls.