Cats are carnivores. Their body structure and physiological characteristics are adapted to digest and utilize animal protein. A cat's teeth and digestive system are suited for tearing and chewing meat, and their stomach acid concentration is high, which aids in protein digestion. Furthermore, cats lack some enzymes needed to digest plant-based foods, therefore their ability to digest plant-based foods is relatively weak.

While some cats may eat some plant-based foods, this is usually for other reasons, such as to promote bowel movements or to meet certain specific nutritional needs. In their natural environment, cats' primary food source is other animals.