I don’t eat meat, for a variety of ethical and environmental reasons, and I’d rather not feed it to my cat, either. Do cats have to be carnivores?
—John McManus, Needham, MA
Unlike dogs and other omnivores, cats are true (so-called “obligate”) carnivores: They meet their nutritional needs by consuming other animals and have a higher protein requirement than many other mammals. Cats get certain key nutrients from meat—including taurine, arachidonic acid, vitamin A and vitamin B12—that can’t be sufficiently obtained from plant-based foods. Without a steady supply of these nutrients, cats can suffer from liver and heart problems, not to mention skin irritation and hearing loss.
As such, a cat’s ideal diet is made up mainly of protein and fats derived from small prey such as rodents, birds and small reptiles and amphibians. Some cats munch on grass or other plants, but most biologists agree that such roughage serves only as a digestive aid and provides limited if any nutritional value.
Of course, providing your domestic cat with a steady stream of its preferred prey is hardly convenient or humane—and cats can wreak havoc on local wildlife populations if left to forage on their own. So we fill them up on dry “kibble,” which combines animal products with vegetable-based starches, and meat-based canned “wet” foods, many containing parts of animals cats would likely never encounter, much less hunt and kill, in a purely natural situation. Most cats adapt to such diets, but it is far from ideal nutritionally.