Make sure your cat is healthy before you tackle any food fads. A number of medical problems can make cats finicky eaters - like ill humans, they won't eat unless the food is especially tempting. A cat with a stomach upset won't eat till it feels better. If a bunged-up nose is the problem, offer pungent foods or warm the food to make it smell more appetising. If your cat's appetite doesn't return within 24 hours or it appears ill, consult your vet as there may be a more serious problem.
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.