Veterinarians offer conflicting advice, labels mince words, some pets are finicky eaters and some have allergies -- with shifting variables like these, choosing a cat food can be a Sisyphean task. There is no "best" cat food, but your cat has to eat and you've got to make a decision.
Cats are obligate carnivores -- they have to eat meat -- and they require certain amino acids from protein, fatty acids, fatty acids, carbohydrates, vitamins, minerals and water to live healthy lives. Apart from that, opinions about cat food run the gamut.
Some veterinarians favor natural foods on principal, even though most scientific studies don't support their purported health benefits. Others recommend making your own cat food at home. If cost is a factor, the former may not possible; if time and convenience are factors, the latter is probably a nonstarter.
Some veterinarians receive payouts or free products from commercial pet food producers, calling into question the authenticity of their endorsements. Regardless, it's best to consult a veterinarian before making cat food decisions.
The Fine Print
If you're picking among commercial cat foods, make sure your choice has the words "complete and balanced" on the label. In the U.S., that wording is regulated by the Association of American Feed Control Officials and ensures pet food so labeled contains every nutrient identified as necessary for good health by the National Research Council for dogs and cats. There are minimum and maximum levels for some ingredients, although the AAFCO doesn't explicitly require particular ratios.
Food marketed for kittens, all life stages, and senior pets have additional requirements. Many other packaging claims aren't explicitly regulated, so you have no assurance of their validity. After talking with a veterinarian and comparing a few labels, you should be able to pick out some cat food candidates.
Habitual Dinner Diners
Cats are creatures of habit and notoriously finicky eaters. They may not be too keen on changing their eating habits. Introduce new food gradually by mixing it with old fodder in gradually increasing ratios. By drawing on established routines and familiar containers, you minimize variables for rejection, according an article from the Ohio State University College of Veterinary Medicine's Indoor Pet Initiative. Alternately, offer new food by itself at a later dinner time, when your cat is hungrier. You can reward a cat who eats some of it with a treat, catnip or a few nibbles of older food at first.
After adjusting your cat's daily dining options, he may start scratching itchy and irritated skin. If so, switch back to the old food and schedule an appointment with a veterinarian -- your cat could be allergic to his new food.
Food allergies are the third most common cat allergy, according to an article from the Cornell Feline Health Center. Skin irritation and legions don't pose a significant risk in and of themselves, but secondary scratching wounds can get infected. Food allergies may lead to food avoidance, which causes a host of health problems. You may have to try a few new foods before finding one that's compatible with your priorities and your cat's allergies. Cats may develop allergies years into a diet, so you may have to revisit food options later, too.