The Ingredients in Cat Food

Unraveling the Mystery of Cat Food Ingredients

Photo of Person Opening a Can of FancyFeast Cat Food

Getty Images / Tom Kelley Archive

Learning to read cat food labels can be a daunting task, especially with those mysterious ingredients. If you were not already aware, you should know that ingredients are listed in order, by weight.

Ideally then, the protein source should be the first listed ingredient in a bag of dry cat food in a regular maintenance diet, followed by secondary protein sources. After that, you can expect to see carbohydrate fillers, oils or fat, preservatives, added vitamins and minerals, as well as taurine (an amino acid that cats need to survive).

When you go to purchase cat food take a look at a few different brands before you buy. Look at the ingredients list and make sure that you are happy with the first ingredient listed. If you read the label and can understand the cat food label, then you are better equipped to make educated food choices that may impact the longevity and vitality of your cat. And, if it all seems daunting, review a few tips for choosing cat food.

Look at This Ingredients List

Take a closer look at the ingredients of a popular "premium"-branded chicken and rice formula cat food found in the supermarket. The top ingredients listed in order are chicken, brewers rice, corn gluten meal, poultry by-product meal, wheat flour, beef tallow preserved with mixed-tocopherols (source of Vitamin E), and whole grain corn. Following that were other meat products, preservatives, vitamins, and minerals. Compared to other food on the market, this food might actually qualify as "medium-to-good" quality—hardly premium or "the best."

Find out more about what each of these ingredients actually consists of. The Association of American Feed Control Officials sets the definitions for food ingredients. This means that a cat food company may not list an ingredient unless it fulfills that definition.

Meat Products

Protein provides amino acids that help a pet build and maintain its muscles, bones, blood, organs, immune system, and hair and nails. There are many combinations of protein sources that deliver a balanced amino acid profile. 

  • Chicken: The AAFCO defines "chicken" as the clean combination of flesh and skin with or without accompanying bone, derived from the parts or whole carcasses of chicken or a combination thereof, exclusive of feathers, heads, feet, and entrails. This is a product you would expect to find in premium quality cat food. Keep in mind, though, that the amount of bone and/or skin may play a part in the quality of the protein.
  • Poultry by-product meal: This is defined as ground, rendered, clean parts of the carcass of slaughtered poultry, such as necks, feet, undeveloped eggs, intestines, exclusive of feathers, except in such amounts as might occur unavoidably in good processing practices. While it is true that cats do eat those parts of the poultry in their natural or wild state, the "rendered" part is not natural and, if you want to make the healthiest choice for your cat, then by-product meal should not be the first ingredient.
  • Beef tallow: This is obtained from the tissue of cattle in the commercial process of rendering. Beef tallow is an inferior source of fat for cat food. It is a saturated fat and is primarily added in food to give it flavor.
  • Fish meal: The clean, dried, ground tissue of undecomposed whole fish or fish cuttings, either or both, with or without the extraction of part of the oil. It must contain not more than 10 percent moisture. If it contains more than 3 percent salt, the amount of salt must constitute a part of the product name (and it may not exceed 7 percent). The salt mentioned here is the ingredient you have to watch for.
  • Egg product: Eggs that are dehydrated, liquid, or frozen, and labeled as per USDA regulations governing eggs. They must be free of shells.


Carbohydrates are an important source of energy for your cat, supplying the building blocks (glucose) for cellular energy. Carbohydrates provide the fiber in pet diets which is important for gut health. Some foods may contain empty fillers, where most of the nutrition has been leached out by other processes. Usually, when an ingredients list mentions a whole grain, that is usually a better choice for your pet.

  • Brewers Rice: This is the dried extracted residue of rice resulting from the manufacture of wort (liquid portion of malted grain) or beer and may contain pulverized dried spent hops in an amount not to exceed 3 percent. This ingredient refers to the rice left over from making beer. It stands to reason that this rice "residue" may not be the same quality of carbohydrate as whole grain rice.
  • Corn Gluten Meal: This is the dried residue from corn after the removal of the larger part of the starch and germ, and the separation of the bran by the process employed in the wet milling manufacture of corn starch or syrup. This what is left over after making other corn-based products. Corn is a popular filler since it is cheap. It is also one of those products that often cause allergies in cats. If you have to choose a cat food with corn as an ingredient it might as well be "cornmeal," which also includes the germ and is not just "a residue."
  • Wheat Flour: The AAFCO defines wheat flour as wheat flour together with fine particles of wheat bran, wheat germ, and the offal from the "tail of the mill." This product must be obtained in the usual process of commercial milling and must not contain more than 1.5 percent crude fiber.

    Preservatives and Supplements

    While vitamins and minerals are added in very small amounts, they account for close to half of the ingredients in a pet food and make up the longest part of the ingredient list on the label. To be listed as "complete and balanced" food, the AAFCO lists 25 essential vitamins and minerals for cats.

    • Mixed-tocopherols (source of Vitamin E): Most premium foods use mixed tocopherols, also listed as a source of Vitamin E as well as Vitamin A as preservatives. They are not quite as effective as the old chemical preservatives BHA and BTA, so always check the maximum shelf life date on the label.
    • Sodium caseinate: Casein is a milk product similar to whey, and the sodium makes it a salty component for flavoring and preservation.
    • Potassium Chloride: This is a potassium salt of hydrochloric acid. Potassium may be essential to all species for heart and nerve function, but used here, it is used as a salty component for flavoring and preservation.
    • Phosphoric Acid: A mineral supplement, consisting of 32 percent phosphorus, this is another additive to help acidify the food to enable the cat to maintain a proper urinary pH.
    • Brewers Dried Yeast: Brewers dried yeast must come from the brewing of beer or ale for human consumption. Having been sterilized and with no leavening power, it is an inactive yeast composed of the single-celled organism Saccharomyces cerevisiae. Brewers dried yeast is a protein source rich in amino acids and B vitamins. Amino acids help a pet build and maintain his or her muscles, bones, blood, organs, immune system, and coat and nails. Without the proper levels of essential amino acids, the synthesis of protein is impacted. In addition, B vitamins support brain function, muscle strength, red blood cell production and digestion. While brewers dried yeast may taste bitter to humans, it is tasty to dogs and cats. A probiotic, It can help reduce stress, reduce sickness, and prevent fleas.
    • Natural Flavors: As defined by the AAFCO, this is a feed or ingredient derived solely from plant, animal, or mined sources, either in its unprocessed state or having been subject to physical processing, heat processing, rendering, purification, extraction, hydrolysis, enzymolysis or fermentation, but not having been produced by or subject to a chemically synthetic process and not containing any additives or processing aids that are chemically synthetic except in amounts as might occur unavoidably in good manufacturing practices. This ingredient is so vague and unclear that it might as well be left off since you have no idea what the ingredient actually is.
    • Remaining ingredients: Vitamins and minerals bring up the tail end of the ingredients list. They are fairly common to all cat foods, they are calcium carbonate, tetra sodium pyrophosphate, L-Lysine monohydrochloride, salt, choline chloride, vitamin supplements (E, A, B-12, D-3), taurine, zinc sulfate, ferrous sulfate, ascorbic acid (source of Vitamin C), L-Alanine, riboflavin supplement, niacin, calcium pantothenate, manganese sulfate, biotin, thiamine mononitrate, folic acid, copper sulfate, pyridoxine hydrochloride, citric acid, menadione sodium bisulfite complex (source of Vitamin K activity), calcium iodate, and sodium selenite A-4623.