Pet Food Ingredients

The ingredient panel of a pet food's label provides general information about the ingredients that were used and their relative amounts. While the information on pet food labels is helpful, the quality of those ingredients cannot be determined from the label.

There is also a lot of misinformation about these ingredients. It is important to note that in the U.S., advertising information, such as websites and brochures, are not generally regulated.


The Association of American Feed Control Officials (AAFCO) decides on the name and make up of each ingredient found in commercially prepared pet foods. Many ingredients are misunderstood by most pet owners. We would like to help you understand the true meaning of the ingredient list found on the side of your dog or cat's bag or can of food.

One confusing concept is the difference between a "whole" meat and the "meal" of that same meat. For example,"chicken meal" is the clean, dehydrated, and defatted portion of the chicken's tissue excluding blood, feathers, horns, nails, etc. This is opposed to "chicken", which is chicken tissue that is NOT dehydrated or defatted. That being said, 10 grams of "chicken meal" actually has more protein, than 10 grams of "chicken" because most of the weight in "chicken" is actually just the moisture (water) found in the meat. According to the United States Department of Agriculture (USDA) Food Safety and Inspection Service whole chicken contains 66% water. You can see where a food containing the first ingredient of "chicken" does not really contain more chicken meat than a food that lists "chicken meal" as the first, second or possibly even the third ingredient on their label. Chicken meal is a higher quality pet food ingredient.

"By-product meal" is another commonly misunderstood ingredient found in pet food. Again, the term "meal" refers to the cleaned, dehydrated state of the tissues. "By-products" are simply the organs of an animal which are not typically sold for human use. Just because some people do not want to eat the heart, lungs, liver, or kidneys does not mean a dog or cat feels the same way. These organs are actually a great source of nutrition for pets. The same rule applies for "by-product meal", it cannot contain any feathers, horns, nails, or anything else which lacks nutrients.

AAFCO publishes their list of ingredient definitions, but they do not post it anywhere for free public access. One must pay to purchase the entire publication. Beware of some of the definitions of AAFCO ingredients found online, they are usually only partial definitions, interpretations of ingredients, and are often inaccurate and misrepresent the true definition of certain ingredients.

Listing Method

Ingredients must be listed in descending order by weight somewhere on the bag of pet food. As mentioned above, "chicken" is heavy due to its high moisture content. Many companies are guilty of supporting the myth that a pet food is only "good" if a meat is listed first. In reality, if Food A lists "chicken, whole brown rice..." there are actually more carbohydrates and other nutrients from the rice than the protein and other nutrients from the chicken as fed in the food. If Food B lists "chicken meal, whole brown rice..." you can be assured that there is more protein and nutrients coming from the chicken meal than from the rice. And there is more protein and nutrients from chicken in a food listing "whole brown rice, chicken meal..." than in a food that lists "chicken, whole brown rice...".


Many food companies suggest that most dogs and cats suffer from adverse reactions (intolerance, allergies, etc.) and have the inability to digest common food ingredients. And that their diet is superior because it does not contain some of those ingredients. However, while the true number of reactions is unknown, veterinary specialists estimate that 1-6% of all dogs and cats have allergic food reactions.

If adverse food reactions are suspected, diets need to be selected very carefully and food trials should be done under veterinary supervision. Not only is an animal's dietary history important, but some commercial diets claiming to be free of certain ingredients actually contain enough of those ingredient to cause reactions in allergic or sensitive animals. For example, there are a few popular diets that specifically claim to have "no soy". Although soy is not listed on their ingredient labels, these diets contain soy in sufficient levels to trigger an allergic response in animals with soy allergies. The most likely cause is the companies' inability to produce pure diets without contamination of ingredients through equipment, etc. during the handling and processing of the diets.

A very strict food trial is needed to diagnose an adverse food reaction. To conduct a food trial, a pet is fed a novel protein (one to which the animal has had no previous exposure) limited ingredient diet or a hydrolyzed protein (the protein has been broken down into pieces too small to cause a reaction) diet. The selected food is strictly fed for a minimum of 8-12 weeks, exclusive of other foodstuffs! Nothing else is fed except the food, water, and, if needed, unflavored medications. Skin testing and blood testing are inaccurate and unreliable, and should not be used to diagnose adverse reactions to food.

Some ingredients get a bad reputation due to overuse, or just plain misuse in pet foods. Many pet food companies support these myths because they don't do the research to learn which ingredients are beneficial to pet nutrition. Instead those companies often rely on the general public to be as ignorant as they are, and rely on marketing gimmicks.

For example, let's look at wheat. Recently, there has been a trend of "wheat-free" and "grain-free" products for pet consumption. Why? Humans can suffer from Celiac disease, which is an intolerance and abnormal immune reaction people have to a specific protein in gluten. Gluten is the protein found in wheat and other grains such as oats, barley and rye. Celiac disease is not a food allergy, it is a genetic disease that runs in families. There is not any documented gluten intolerance in any breed of cat. Gluten intolerance has been documented as an inherited condition of Irish Setters, but there is no evidence that it is inherited in other breeds. It is considered a rare disease in dogs. In reality, wheat gluten is nearly 2/3 protein! It is also nearly 99% digestible, which is more digestible than some meat products! It is a great source of nutrients that can be easily absorbed and used by your pets.

Corn is another commonly misunderstood ingredient. Corn contains high levels of many important nutrients, like linoleic acid which is crucial to any pet diet. In fact it is one of the required essential fatty acids. Much like people need to eat foods containing certain vitamins, our pets need linoleic acid in their diet. Corn is also a great source of easily digestible protein, even comparable to chicken meal!

There is no published evidence that dietary grains cause any problems for normal healthy dogs. Most dogs do very well on diets containing grains. Dogs can be allergic to any of the proteins in the diet, but meat-based protein allergies are more common in dogs than grain protein allergies.

Most of what owners come across from companies manufacturing grain-free diets is just marketing-hype. If any manufacturer is making claims that grains are bad for dogs, they should be contacted and asked for the proof (documented, published scientific studies) behind their claims. If all the manufacturer can offer is testimonials, which are not scientific and cannot be considered proof, they should be disregarded.

There are certain ingredients which truly do not belong in a healthy diet. One such ingredient is sugar. You may be surprised to check your pet's bag of food and find sugar listed in the ingredients. The ONLY reason given by one manufacturer, who makes a diet that has sugar listed as its 8th ingredient, is for the "consistency of the kibble" and not for any nutritional value. In other words, the company puts sugar into the food just so that the kibble remains semi-soft. Sugar is not a good thing for people to have in every meal and it is certainly not good for our pets. Pets are also prone to gaining too much weight, which increases the risk for developing diabetes!


This is a very important quality of your pet's food. It CANNOT be determined by the label though! You can only read the actual list of ingredients, nothing in their names can tell you whether or not the ingredient is in a form which can be easily digested. What good is that ingredient if your pet cannot break it down and use the nutrients it contains?

To explain this concept, we can look at a peanut. If a person swallows a peanut whole, chances are, it will exit the body whole, without providing any real nutrition. But if that person ate peanut butter instead, the body is then able to extract protein and other nutrients. Unfortunately, it is impossible to determine the true form of ingredients listed on a pet food bag. The processing that all pet food is subjected to so that it can be sold as kibble or canned food is something of a mystery for consumers. Consumers like us are at the mercy of the company. We can call the company, ask to see their research and results of food trials, inquire what research went into making the particular diets, but nothing on their label will tell us anything about how our pet's body will be able to digest the food.

That being said, all pets are different. There is not one diet that is all things for all pets. It is important to pay attention to what our pets are telling us. If their stool remains too soft or too firm, if their coat remains dull and their skin flaky, if they are overweight and just keep gaining more, chances are their food may not be the best diet for them. Many other clues about the appropriateness of your pet's diet can be obtained from your veterinarian, and by looking internally at your pet's organ function through blood work.

We (the food company, the consumer, and the veterinarian) must work together in order to provide the best possible food for our pets!