Obligate Carnivores and their Needs
According to Britannica, obligate carnivores "cannot obtain all the nutrients that they need from the plant kingdom and bacteria. In particular, obligate carnivores lack the enzyme needed to split carotene obtained from plants, into vitamin A." They are animals who's digestive system can't handle digesting only plants for nutrients. Cats are one of the prime examples, which includes house cats just as much as big cats in the wild. A cat's diet is trickier than just remembering that they need meat to survive, but they also need the right balance of nutrients. With lots of time for prep and research to make sure your cat is getting just the right amount of each nutrient (not too little, not too much), it is possible to make your own cat food, but it is time consuming. The much easier and faster way is to buy cat food from the companies who make it. That way the only work left is to read the labels to double-check all needs are being met.
One of the considerations to keep in mind for nutrients is that because cats are obligate carnivores, grains are very bad for them. Their intestines aren't designed to handle the carbohydrates of plants, and particularly of grains. Food with a high grain content can lead to inflammatory bowel disease, among other health problems. Cats need vitamin A, and usually obtain it from liver, since they can't process the vitamin through plants. Vitamin C is necessary for survival, but one of the neat things about the biology of cats is that they, unlike us humans, produce their own within their bodies. Niacin, Arginine, and Taurine are all nutrients cats need to obtain from a meat diet.
Cats are wonderful and fascinating creatures, and if we are or decide to become their caretakers, it's important that we provide what is best for them.