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Pet Health

Demystifying Pet Food Fillers

Val Cairney January 21, 2022 104

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Hello everyone and welcome to this first episode of 2022.  I hope everyone is staying safe and smart and all our furry friends and family members are also well and happy.

Unfortunately I do have a sad update to share.  On December 15th my little orange cat Esme lost her battle with a strange cancer she had in her nasal passage.  She had been fighting with this cancer for about 2 years along with her stage 3 renal condition.  I had mentioned several times how I had been quite successful keeping her renal situation under control for 2 years using Omega Alpha’s Kidney tone.  She had a stroke at the end of November and became partially paralyzed.  But, she just kept trying and fighting and we figured we would just roll with it and help her whichever way we could, which meant diapers and exercises but she was pain free and wanted to give it her all so we made sure we gave her our all.  She unfortunately had another stroke which took away her awareness and while cuddled in a blanket, warm in her bed she peacefully passed away.  She was such a little fighter and I have talked in previous episodes how I got her at the barn where I was boarding as she took refuge there during a very cold January.  She was tenacious and sweet and we all miss her.  

So, on to the topic for this episode.  Seeing as we are now into a new year, I have been making note of specific questions I am often asked, again, and with many new pet parents out there and some back to being pet parents, one of the top topics is always about food.  Pet parents nowadays are very interested in their pet’s nutrition and this is a good thing, because good nutrition can really keep the vet visits down to a minimum.  When it comes to questions about food, one of the most stated things often comes this way.  “I would like to get a good food for my dog, I don’t want any fillers.”  Absolutely.  Now, here is the thing.  There isn’t a single product in our store that has fillers.  Not one.  Hmmm?  Why is that? Well first, a filler means there is absolutely no nutritional value to the ingredient.  Well that puts a real spin on things doesn’t it?  When we see corn, corn gluten meal, wheat, soy in a product, these are often the top ingredients that people relate to as fillers. I’m going to spend some time on these in a minute, because a particular ingredient seems to always get tagged as a filler and quite incorrectly so and this is “meal”.  If you read your ingredient panel on your bag of kibble you may see, Chicken, chicken meal, as the first two ingredients.  I know of only one brand that does not have any “meal” in its list.  So, let’s define meal and then go on to the other suspect ingredients.  Many people see the word “meal” and automatically think that “meal” is a filler.  Meal means that “[r}aw material is ground or what is also called “sizing” cooked, pressed to remove fat, the remaining material is ground again and becomes, “meal” ingredient.  The meal ingredients are a powdery substance.”  Every brand just about in pet specialty uses meal to get as much concentrated protein into the kibble.  Here is what Tundra’s food says on his bag.  “De-boned salmon, salmon meal, etc.”  The meal in this case would be salmon that has been through the extrusion process. On many brands you may see chicken, chicken meal, which would mean the same as the salmon example.  Part of what is in the product is fresh chicken and then the extruded chicken, the fat removed and cooked chicken.  You may also see chicken by-product meal.  The difference here is “chicken meal means, “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.  By-products meal by definition is “made of the waste material left over after the parts for human consumption have been removed”  Now, the origin of the by-product can be a bit grey so, when a product says chicken by-product meal, first thing to consider is the overall quality of the product.  Was it purchased in pet specialty?  Is this product available through grocery for example?  These two questions can be vital.  If the product is at a grocery store level then the by-product can be suspect.  If the product is specifically a pet specialty product, then the quality of the by-product and the actual by-product may be of acceptable quality.  AFFCO, the Association of American Feed Control Officials defines by-product as “secondary products produced in addition to the principal product”.  This means that a company may use wings, or legs as their by-product as the breasts of the chicken were the primary and the wings, thighs and legs are the secondary.  It would be a very plausible leap to make that a company that does this would be producing at pet specialty level.  Now, if the by-product is only defined as animal, then you are in uncharted territory.  AFFCO requires that the ingredients list include the species of animal that meat and meat by-product comes from unless the meat or meat by-products comes from cattle, swine, sheep or goats. So, the first thing to strike off our list is the idea that “meal” is a filler.  It is not.  “Meal” is a way of getting animal protein in kibble, that’s it.  It is not a filler.   Now, apart from animal protein, we can see other ingredients that are again, thought of as fillers. This is where we return to the corn, corn gluten, wheat and soy ingredients.    

Does wheat, corn and soy have no nutritional value?  Well, let’s take a look at these top ingredients that are often thought of as fillers.   Let’s start with one that is rarely seen in foods that are in pet specialty and work our way up.  Soy,  Or soybean hulls.  Some food will list that there is no soy in their product very specifically.  So, obviously the manufacturer is relating that soy is a bad thing and their product doesn’t have it.  In some pet foods soy is added and in the scheme of things, soy or soybean hulls are a good source of insoluble fibre helping to add a high fibre ingredient.  According to, “soy products are one of the world’s oldest and most widely used sources of high quality protein.  Its complementary amino acid profile combines well with other proteins and grains.  Soy products are a superb source of bodybuilding protein and essential amino acids.  It provides coat-nourishing vegetable oil and healthful fibre.  So, soy is a plant protein first and foremost.  It has a high nutritional value so that right away takes it out of the “filler” category but the inclusion level shouldn’t be more than 5 to 15% as it has a high flatulence characteristic.  So, if your dog is rather “farty”  check to see if their food has soy or even other legumes that could be the culprit.  Soy is safe so to speak for dogs and cats to eat and plant based protein is significantly cheaper so it can be an alternative for companies to produce a less expensive alternative for consumers.  

Alright, so, what’s wrong with soy?  Well, soy as with our other ingredients, is a highly GMO’d product. Genetically modified organism.   About 90% actually.   According to after the oil and fats are extruded from soy for humans, what is left is the meal, which we’ve talked about, and this is primarily used in animal feed which includes cat and dog food.  Here is information from truthaboutpetfood. Soy has high levels of manganese and aluminum, which can lead to brain damage.  Apparently, ingestion of soy products is linked to seizures in both dogs and cats.  And as per mentioned above soy can cause gastric distress, yup, farty dog. According to, soy, while being highly gmo’d, “their crops are covered in pesticides, everything dies, except the soy.  It is left to absorb all those chemicals that were sprayed onto the crops.  And if it’s in the soy – it will go into your pets.” It is also speculated that soy “wreaks havoc with the endocrine system causing problems for the thyroid function.  Okay, so the bottom line on soy is that there are some experts and pet food manufacturers that believe that soy is a healthy form of plant based protein.  Others believe that soy is too high on the GMO list and full of pesticides.  Some believe that cats in particular should only be eating animal proteins due to their carnivore nature and dogs as obligate carnivores meaning that at least 70 % of their diet should consist of meat, also should not have their protein source be dependent on a plant based protein. The animal protein source replicates their ancestral diet more closely.  It is also a belief that soy is a lesser expensive form of protein so it is used in lower quality pet food.  The opposite of that is that it gives a less expensive alternative to pet parents for feeding.  So, there are both sides of course, but the one thing that is consistent between the pro and con soy information is that soy can be a cause of flatulence.  And the other thing to mention is that I do not have a single product in store that has soy in it.  So, the big pet specialty brands do avoid soy.  

Now, let’s move onto wheat.  Wheat in and of itself is used as a high quality carbohydrate source in dry pet foods and treats and biscuits.  Now, as we know from our human standpoint, wheat contains high amounts of gluten which (can) damage the small intestine, alters gut flora and can lead to autoimmune disease.  Some believe there is no nutritional value to wheat in pet food.  So why is it there?  According to, “wheat is a common staple in many lower-grade dry dog foods as it is inexpensive and is ideal for forming biscuits and kibbles.  It is however, regularly linked with dietary intolerance in dogs which makes it a highly controversial ingredient.” “In wheat intolerant dogs (also called celiacs), the gluten protein contained in the grain damages the lining of the small intestine and prevents it from absorbing parts of food that are important for staying healthy.  Wheat intolerance can therefore lead to wide-ranging health problems most commonly affecting the skin, coat and digestive system.”  So, if we go back to the interviews with Joanne Carr from Omega Alpha and Ayurvedic practitioner, and with Theresa Gilligan, one of the main things they spoke about was how the gut has the ability to throw many things off particularly skin.  As well we often look directly to the food a dog is eating when a pet parent says their dog has constant ear infections.  Wheat can be a culprit here so a change of food may be warranted.  The biggest problem with wheat is that pets are really exposed to wheat in food and treats.  This overexposure is what can contribute to a wheat intolerance.  So, does wheat have a nutritional value?  Yes it does.  It is a source of carbohydrate.  Is it the best source of carbohydrate?  That depends on how you feel about it.  Is it GMO’d?  Most likely not, but check your own area as in Canada for example there is no GMO’d wheat.  The problem stems from overexposure.  If a dog or cat is demonstrating skin issues, scratching, loss of hair, itchy ears, then it is possible they have developed an intolerance to wheat and can even be Celiac.  In this case if you wish to include grains in your pet’s diet, looking to the ancient grains would be a solution with quinoa, spelt, amaranth or barley, oatmeal or millet for example.  

Okay, so let’s go to the big one that causes arguments on both sides, and that is corn.  Corn is one of the top ingredients people see and right away state it is a filler.  Well keeping in mind the definition of a filler, it would mean that there is no nutritional value to corn.  According to, “corn is a rich source of fatty acids, especially linoleic and linolenic for healthy skin and coat.  These essential fatty acids serve important roles in the immune system and central nervous system.  Cooked ground corn is highly digestible so pets can easily absorb corn’s important nutrients.” Corn is basically a carbohydrate.  The thing is however, that the corn has to have a balance with other grains for it to be optimal.  According to DogFood Advisor, corn in the whole grain is not highly digestible, and only becomes so, after it is first refined into a meal or flour and then cooked.  So, if the bag says whole corn, it would still be ground and then cooked.  Now as noted, manufacturers like to point out the nutritional completeness of corn.  In terms of the biological value of corn, it’s not really that unique.  On the biologic table, corn falls to about 54 out of 100 in value whereas eggs, for example, rate 100 and beef 78.  So, in terms of the idea of nutritional completeness that is argued by many companies, it isn’t actually very remarkable in composition.  Okay, so at this point so far corn has its merits, nothing to worry about.  According to DogFoodAdvisor, “corn makes any pet food you find it in, less expensive to produce.  And it does this by diluting a recipe’s more costly meat ingredients.  Okay.  But, let’s look a bit deeper.  According to Truth about Pet Food, corn is graded.  In the U.S a number grading system is used with number 1 the highest quality and number 5 the lowest quality.  In pet food, all grades are accepted.  This means that depending on the quality the manufacturer wishes to use, it’s possible that “sample grades could be used, that contain 0.1% of stones, 2 or more pieces of glass, 4 or more particles of a commonly recognized  toxic substance, 0.20% animal filth, has a musty smell and or is distinctly low in quality”.  Pet food labels are not required to disclose which grade of corn has been used.  “Because inferior grades of corn analyze almost identical protein percentages as high quality corn, pet food manufacturers can switch between grades of corn or combine grades of corn in different batches of pet food without altering their formulas.”  So, what quality of corn is being used in a formula is a mystery.  And I think this is a good place to talk about the confusion that many people experience when they look at ingredients on a pet food bag.  On the face of it, a product from grocery, big box or pet specialty could look very similar.  The question presents, why to spend more money on something from pet specialty when a similar product is available in grocery or big box?  Well, this is where the quality of that ingredient comes into play.  Remember a product only has to reach a certain level to be in grocery and has to reach a certain level to be in specialty.  So, this is exactly the situation where the corn for example, could be at level 1 or 2 in specialty and 4 or 5 in grocery or big box.  So, definitely something to consider.  

Now, let’s look at the issue of glycemic index.  Corn as we know has a high sugar level.  There is quite a bit of information and research with regards to this topic.  So, I’m going to rely here on a paper published by the University of Saskatchewan in Canada, on “Comparative Biochemistry and Physiology, Part A.”  An experiment was done on cats and dogs who had fasted, to see reactions to single feedings of different starch sources.  It found that, “after feeding starches or whole diets to dogs, postprandial glycemic response, glycemic index, insulin, methylglyoxal, and D-lactate followed reported glycemic index trends in humans.  In contrast, cats showed very low to negligible postprandial glycemic responses.  Thus, the concept of glycemic index appears valid in dogs, but not cats.”  So, it follows that dogs who eat corn in their diet, could experience a glycemic or sugar spike which can become concerning for a pet parent who is trying to keep their dog’s weight under control, or their dog is experiencing high energy spurts regularly.  

Let’s look now at the big issue, which is the fact that corn sits as one of the highest GMO’d grains.  According to,  dogs often eat GM food in the form of corn.  “Experts say, and a recent long-term peer-reviewed report, found that a diet of GM corn led to higher rates of severe stomach inflammation in pigs, which are physiologically similar to dogs.  Activist Jeffrey Smith spoke at a seminar on GM foods and human health.  Smith the founder of the Institute for Responsible Technology, warns on his website,, that “nearly all GM crops are described as “pesticide plants.”  They either tolerate doses of weed killer, such as Roundup, or produce an insecticide called Bt-toxin.  In both cases, the added toxin – weed killer or bug killer – is found inside the corn or soybeans we consume.”  Another part of Smith’s presentation also included information that referred to a report in the New England Journal of medicine, “which found that genes inserted into crops can carry with them allergenic properties.”  There is quite a bit more information with regards to this observation but this really makes sense when we are seeing more and more pets, dogs in particular that are experiencing intolerance or allergy type symptoms like, itchy ears, paw licking, skin rashes and itching, that in days gone by would never have been experienced.  The bottom line is that the food is just not what it was and pets are reacting.  

So, the bottom line on corn is that it is a carbohydrate.  It serves this purpose on the nutritional scale so that means it is not a filler.  Several pet food companies, some quite high end, will argue wholeheartedly that corn is a good ingredient and serves a good nutritional contribution.  However, corn does have a high glycemic index for dogs and it is highly GMO’d.  

Now this leads me to my pet peeves section.  

Pet Peeves

Trying to figure out pet food is a mind field.  You just can’t get a straight answer and pet foods are not obligated to divulge many of their ingredient quality or ingredients period.  The thing is, that there really isn’t such a thing as a filler in pet food, but there is such a thing as quality.  And I can tell you, every brand representative will argue that their brand is the best and that every ingredient is of great nutritional value.  For me, I prefer not to pay the price for a food for my pets that contains wheat or corn, when I can pay a similar price for a food that is grain free or uses ancient grains like spelt, kamut, quinoa or oatmeal, or barley.  And something else that I would definitely not go near and that is anything that has animal digest or animal fat.  When it comes to the word “animal” in pet food you are really in unknown territory.  Animal digest is often used as a flavour enhancer.  By definition animal digestion is produced by the chemical or enzymatic hydrolysis of clean animal tissue that has not undergone decomposition.  According to 11 Red flag ingredients in your pet’s food, “vague and unidentified meat is likely inconsistent in quality, meaning you could be feeding scraps from a variety of sources.  These ingredients might even include 4D animals, (diseased, disabled, dying, or dead before processing). And yes, there is a certain food company that likes to argue the benefits of animal digest, but personally, I don’t care what you say, it’s a no go!  But, as always, do some reading and make sure you check who has posted the information.  So, again, do your homework so you can make an informed choice for your pet because as I say, knowing is caring.    

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Val Cairney

Hi everyone, and welcome to Val Talk’s Pets, the forum for pet parents and enthusiasts alike. So, I have been working in the pet industry now for almost 10 years and, on a daily basis, I handle a lot of issues and questions arising from pet parents. I am not a veterinarian but I do have certifications in Canine, Feline, Small Animal, Fish and Herptile and Avian Health and Nutrition from the University of California, Davis Extension, the Vet College.

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