Cats are not small dogs, and they are not humans in fur. They are obligate carnivores — meaning they have evolved over millions of years to derive their nutritional requirements almost entirely from animal tissue.
The Obligate Carnivore
An obligate carnivore is an animal that requires nutrients found primarily in meat. Cats lack specific enzymes in their liver that would allow them to synthesize certain amino acids and vitamins from plant sources the way dogs or humans can. The most well-known example is taurine — a amino acid found almost exclusively in animal muscle tissue. Without adequate taurine, cats develop fatal heart disease called dilated cardiomyopathy.
Cats also lack the specific liver enzymes needed to efficiently metabolize carbohydrates. While a small amount of carbohydrates in cat food is not harmful, a diet that is high in grains or plant-based ingredients does not match what cats have evolved to eat.
Protein Requirements
Adult cats require a minimum of 26% protein on a dry matter basis — compared to about 8% for adult humans. Kittens require even more — around 30%. This protein must come from animal sources to provide the full spectrum of essential amino acids. The protein in corn, wheat, or soy is not a substitute for the protein in chicken, turkey, or fish.
Reading Cat Food Labels
The ingredient list is ordered by weight before processing. The first ingredient should be a named meat source — chicken, turkey, salmon, duck. Be wary of foods where the first ingredient is a grain or plant product. A statement like "chicken meal" (dry concentrated protein) is actually higher in usable protein than plain "chicken" (which is mostly water weight).
Wet vs. Dry Food
Wet food provides significantly more moisture per serving, which benefits urinary tract health. Many cats are chronically mildly dehydrated on dry-food-only diets. That said, high-quality dry food is convenient and can be nutritionally complete. Many veterinarians recommend feeding some of both — wet food for moisture and hydration, dry food for dental benefits and owner convenience.