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Nutrition FAQ



Background: Five Key Facts About Cats and Cat Food
Frequently Asked Questions
Part 1: Reading Cat Food Labels
Part 2: Understanding Ingredients
Part 3: The Right Food For Your Cat
Part 4: Real-life Decisions
Part 5: Other Resources

  • Do you feel overwhelmed when you walk into the pet store to purchase food?
  • Do clerks at one pet store tell you to feed your cats one brand, and clerks at another store recommend a different one?
  • Does your friend rave about an all-natural pet food product?
  • Do you want to feed only organic food?
  • What about that celebrity's brand of cat food that sounds so wonderful?
  • How do you compare three brands that all claim to offer the best ingredients but sell for widely varying prices?

If any of these questions strike a chord with you, you are not alone. Nutrition is recognized as a very important part of maintaining good health, and we all want to feed our cats what's best for them. In this handout, Cat Hospital of Chicago veterinarians:

  • Offer background on nutrition for cats,
  • Answer some of the most commonly asked questions, and
  • Provide recommendations for your cat's nutritional health.

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Background: Five Key Facts About Cats and Cat Food

  1. Cats are obligate carnivores. This means they must eat meat to obtain key nutrients (primarily amino acids) for their health. Without a meat-based diet, cats are prone to heart failure and blindness. Additionally, because domesticated cats are descended from the African wild cat, which lives in the desert, they cannot survive exclusively on fish-based foods without risking brain disease and other serious health problems. Vegetarian diets are out as well.
  2. The pet food industry is just that "an industry" made up of companies and well-intentioned individuals whose ultimate goals are to be successful in business and promote a good product. This means that, like every other company that is selling to a consumer, pet food companies must make their products stand out from the crowd.
  3. There is very little oversight in the pet food industry. Anyone with a marketing plan can put together a diet and market it and that means anyone, regardless of whether they have any background or training in veterinary nutrition. In fact, there are fewer than 100 board-certified veterinary nutritionists in the U.S. (Board-certified nutritionists must pass a three-year intensive training program beyond veterinary school, it's the highest standard of veterinary nutrition training.) There are hundreds of brands of pet food, however, so not all of them could have a board-certified nutritionist overseeing recipes, evaluating the quality of the ingredients or judging the final product.
  4. The highest standard for evaluating the nutritional quality of a diet is a feeding trial. A feeding trial is performed at the company's expense and is quite costly, so many companies don't perform them. The companies that put their products through rigorous quality testing, however, are likely the ones that are most interested in confirming that their product meets minimum nutrition requirements and has been proven to be properly digestible by cats. This is important because nutrients need to be readily available in the cat's system and we need to know that the product performs nutritionally just as it did in the laboratory dish. With some foods, there is a big gap in how food interacts with the cat's body and how it behaves in a lab. A product that has been evaluated for health and safety will have this information listed on its label.
  5. The only effective way to compare diets is with a nutrient analysis in a laboratory of the final product, not individual label ingredients. Labels are notorious for being incomplete and confusing.

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Frequently Asked Questions

Part 1: Reading Cat Food Labels

Q: What's the best way to read and compare cat food labels?
A: A label should list the manufacturer, its phone number, and for which life stage the diet is intended (kitten, adult or senior) because nutritional requirements vary by age. The ingredients are required to be listed in order according to weight, and the label should indicate whether the food is a balanced diet. (If it is not labeled as a "balanced diet," the food is not intended as a maintenance diet and should not be fed as more than 10 percent of a cat's caloric intake.) It should say whether it meets Association of American Food Control Officials, or AAFCO, minimum standards, and the label should note whether the diet has been through feeding trials.

Information about the food's percentage of protein or fat and ash content tend to be less important. These figures are almost always listed as percentages with qualifiers like "no more than" or "no less than," which are difficult to evaluate.

Also, it is helpful to realize that words such as "wholesome," "holistic," "premium," "human-grade," and "all-natural" are primarily marketing terms that are used to appeal to you, the consumer. There are no standard definitions for these designations, and manufacturers can use them in any way they wish. Even the word "organic" can be somewhat misleading: Manufacturers can call a product organic even if only one ingredient is organic (although the label must state that only a certain ingredient is organic).

Q: Is it true that meat should be the first ingredient on the label?
A: No. This belief is left over from the early years of kibble-based foods. Back in the 1960s, some poor-quality foods were exclusively plant based. Some competing pet food companies started advertising that meat was the first ingredient in their diets, implying that this made their food better than other manufacturers, products, but there is no way to discern the quality of pet food by the ingredient list: Even though beef may be listed among the ingredients, you may not know what type of beef, what cuts of meat are included or how nutritious it is.

Plus, food labels list ingredients in order by their weight in a food. So, even if meat is listed first, the food may contain only a small amount of animal protein because the meat may have a higher water content (and thus a higher weight) compared with the other ingredients.

Q: Can we judge the quality of cat food by the order of the ingredients on the label?
A: No. Food quality can only be judged by laboratory testing.

Q: I've heard that "meat byproducts" include things like beaks, feathers and other indigestible parts of the animal. Is that true? If a food contains meat byproducts, does that mean the food is inferior?
A: No. The AAFCO has clearly defined meat byproducts (also called "meal"), and meat byproducts do not contain inedible ingredients.

Byproducts refer to non-skeletal muscle meats, which include the heart, lungs, liver and other internal organs, as well as fat and smooth muscles. These are often nutritious, even if we rarely eat them as part of our Western diet. From movies and television, you might know that when lions eat their prey, they first devour the abdominal organs, which are nutrient-dense and likely would be our cats' preferred diet. There are still many cultures in the world where people eat all parts of the animal, and they're even considered delicacies, tripe, kidney pie and oxtail soup are just a few examples.

So it's possible that certain cat foods that list byproducts first on the label are actually more nutritious than diets that list meat as the first ingredient.

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Part 2: Understanding Ingredients

Q: Are ingredients like corn and grain bad?
A: No. While most cats would not eat too many cereals or vegetables in the wild, they are capable of digesting these ingredients. In fact, mice "cats" favorite food eat cereals, so these ingredients are part of a cat's normal diet.

So, although it's true that they are found in higher concentrations in most dry kibble brands than what cats would normally eat on their own, corn and grain are not harmful. Diets that have been through feeding trials are subject to rigorous control testing, so they have been proven to be nutritious. In fact, cereal-based kibble foods have a 50-year track record of improving pet health.

Certainly, carnivores thrive best on a protein-based diet, but grain-free foods are not necessarily better. Dry kibble still needs an ingredient that binds the other ingredients together, and cereals such as rice or oats are sometimes used in place of corn or wheat. In some diets, starches such as yams or potatoes are substituted.

Grain-free diets tend to be high in fat and calories. At Cat Hospital, we commonly see cats who have been switched to grain-free diets gain a couple of pounds, which would be the equivalent to a weight gain of 20 pounds or more for a human adult. Also, taking in too much protein can be stressful to the kidneys, especially if there is any pre-existing kidney disease, which occurs commonly in older cats. We also have seen cats on grain-free diets become more prone to bladder problems including excess urinary crystal formation and bladder stones.

One other concern about grain-free foods is that almost all of them are made by smaller companies with little to no professional nutritional oversight and limited quality control capabilities.

Q: Can corn and grain cause food allergies in cats?
A: Actually, cats' most common allergies are to proteins such as fish, poultry and beef corn is far less likely to cause an allergy. There also is no research to show that pets can develop a wheat gluten sensitivity, with the exception of one genetic line of dogs.

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Part 3: The Right Food For Your Cat

Q: What's the best food for kittens?
A: Like children, kittens should be exposed to a variety of flavors and textures of food early in life (up to 14 weeks of age), so they accept various food textures as they get older. It can be very challenging to train an older cat to transition from dry food to wet, so it's better to introduce different foods while the cat is still young.

It is critical for kittens up to age 1 to eat a growth diet, which has more protein (therefore more calories) than standard adult diets. But kittens should not be allowed to eat unlimited quantities (also called "free feeding"), because "just like children" they can eat too much and become overweight. This is especially true when kittens reach the age of 5 or 6 months, when their growth rate and metabolism slow significantly, and/or after they have been neutered.

Q: What if I'm feeding a kitten and an adult cat in the same household?
A: The word "copycat" was coined for a reason! Kittens like to mimic adult cats and eat their food.

If your kitten likes to steal the adult kitty's food, you may need to separate the cats at meal time, or closely monitor who is eating what. And don't free feed your cats. Instead, meal feed, which means putting down food at certain times, and then picking it back up when the cat is finished eating. Although eating multiple small meals throughout the day better mimics the natural feeding pattern for cats, free feeding cats unlimited quantities of food 24/7 often leads to undesirable weight gain in those that don't self-regulate their eating. Meal feeding several times daily is ideal. For more information, see the library article Weight Management in Cats.

Q: I am a vegan and don't want to feed my cat meat products. Can I feed my cat vegetarian food?
A: No! Cats require meat proteins in their diet, and those who don't receive sufficient meat protein have a higher risk of heart disease, brain damage and blindness, and many other health problems related to nutritional deficiency.

Even so-called formula foods that are labeled "vegetarian" are not truly vegetarian. Balanced cat diets that meet AAFCO standards must contain the essential meat-derived amino acids taurine, arginine and arachadonic acid, as well as other micronutrients required by cats.

Q: Should I give my cat a daily multivitamin?
A: If your cat is eating a balanced diet, a multivitamin is unnecessary, and it might even result in an overdose of certain key vitamins. If you prepare your own pet food, however, check with a feline nutritionist about whether multivitamins are recommended.

Q: I have heard that wet food makes cats gain weight and ruins their teeth. Should I really feed my cat wet food?
A: Those objections were common years ago, but veterinarians today recommend wet food for cats. Wet food helps improve cats' water consumption and helps them feel full, which means that they're less likely to overeat. Canned foods also are lower in calories because of their water content, so they can be a very effective way to keep your kitty lean.

Most domestic cats are poor water drinkers because they descended from desert-dwelling cats who lived with little access to water. So cats extract most of their daily water intake from their food. But when they eat only (or primarily) dry foods, cats can develop problems such as bladder stones, bladder irritation or cystitis, constipation and early-onset kidney disease.

Finally, when it comes to dental health, there is little difference between all-wet diets and standard dry kibble. Unless cats have their teeth and gums brushed with a toothbrush, they will develop dental disease at roughly the same rate, regardless of what kind of food they eat.

Q: I am reluctant to feed my cat commercial, processed foods. Is raw food OK for my cat?
A: Yes, raw food can be OK. But remember that unbalanced diets are harmful, and raw food diets are not necessarily balanced diets. Commercial raw food diets must adhere to the minimum dietary standards for cats and specifically for your cat's age.

Raw diets also are more likely to result in food-borne illness because they tend to have higher concentrations of harmful bacteria such as salmonella and E. coli. Only cooking can adequately kill infectious parasites and bacteria. Even frozen and freeze-dried food can still contain harmful bacteria that can "reactivate" when rehydrated. For this reason, Cat Hospital of Chicago always recommends cooking raw food to an internal temperature of 165° F (and then cooling) before feeding.

Many cats and dogs eat raw foods and never have problems, but there also are many pets that become ill. Just because cats would eat uncooked foods in the wild doesn't mean they can't get sick from them. (For example, song bird fever is a salmonella infection picked up from eating wild birds.)

There's another potential danger from contaminated raw food: Even pets that appear healthy while eating it can shed infectious bacteria in their stool and through their coats, which can cause infections in people. And raw foods should never be fed to cats who are ill, young or elderly, or in households with young children, seniors or people with serious chronic health problems, including cancer.

Preparing raw food in the home is not necessarily any safer than buying a commercial product. A common mistake made by people who prepare raw food for their cats is feeding only muscle meats, which are not necessarily the most nutritious meats. Plus, it can be difficult to ensure that a home-prepared diet is properly balanced.

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Part 4: Real-life Decisions

Q: I've heard that pet food companies give special perks to veterinarians and veterinary students so they'll recommend certain brands. Should I still trust my veterinarian's suggestions for which food to buy?
A: It is true that several pet food companies have traditionally offered free or reduced-price pet food to veterinary students, and some sponsor educational seminars or dinners. And, it is true that people (in any profession) who are exposed to a brand or product tend to be more likely to recommend that brand.

Ethical veterinarians, and the majority of veterinarians are ethical professionals, will recommend food based on their comfort with the product, how strict the quality control measures are and the food's performance in their patients. Still, it's important to remember that within any group of doctors, even if they all have the same background, same training and same exposure to advertising, there will be differing opinions on what foods are the "best."

Q: With all of the pet food recalls recently, I am afraid to feed my cat commercially produced cat food. What do I do?
A: Pet food recalls are frightening for all of us, but it is important to realize that recalls occur less often for pet foods than they do for human foods. Cat Hospital's best advice is to be comfortable with the diet you are feeding. Be sure that the company tests its prepared foods and learn about the manufacturer and its quality control procedures.

One benefit of food made by reputable companies is that issues that could prompt a recall would likely be discovered, and reach customers, much more quickly than they would for food from other sources.

Some people recommend feeding a mixture of foods from a variety of companies or rotating foods between reputable companies, which could reduce the risk of encountering a problem with any single product. One drawback of that approach is that some cats have a difficult time adjusting to changes in diet, either because they are fussy about their food or due to sensitive digestive tracts. It also can be hard to stick to a weight management plan if a cat's food is being changed regularly, because all foods have different calorie contents.

Q: With all of those warnings about what not to feed my cat, I'm confused. What should I feed him?
A: Until we can provide mice and crickets for our cats' daily meals, no diet is perfect, all other cat food is essentially a compromise between what your cat would eat on its own and what we can offer.

The bottom line is that you should feed your cat the best diet you can afford that fulfills your cat's dietary and lifestyle needs. In general, Cat Hospital of Chicago recommends a combination of wet food (with warm water added to improve water intake) and dry food (particularly "dental" dry kibble that reduces plaque and tartar accumulation). Wet food should constitute at least 50 percent of the diet.

Here are some other do's and don'ts:

  • DON'T free feed your cats (see Part 3, question 2 above). Leaving unlimited quantities for them to graze on can be detrimental because most cats will overeat.
  • DO take your cat for regular weigh-ins at Cat Hospital. Weigh-ins, which are free with our nurses, can help prevent obesity and the related problems of joint damage, bladder disease, diabetes and heart stress.
  • DON'T feed from one bag of food for longer than a month. Spoilage and staleness can be a concern for dry food after a few weeks. Food stored in an air-tight container in the freezer will last longer, but containers that have been in the freezer need to be thoroughly cleaned between batches of food, and Cat Hospital still recommends purchasing only enough food to last for about a month.
  • DON'T rely on generic recipes or recipes found on the Internet if you're preparing your own cat food. Even many of the well-known holistic pet books contain generic, outdated recipes.
  • DO consult with a board-certified nutritionist at www.petdiets.com or www.balanceit.com to be sure that you are choosing the best diet for your cat based on age, health and flavor preferences. Cat Hospital can help you ensure that your cat does not develop any nutritional deficiencies from whatever diet you choose.
  • DON'T decide on your own to leave out ingredients in a diet that has been balanced for your cat.

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Part 5: Other Resources

Q: Where can I learn more?
A: Cat Hospital of Chicago recommends the following websites for more information:



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