Why We’re Misjudging Dog & Cat Food Quality
Right now, the industry is getting it wrong.
Ingredients matter. Quality matters. That’s not up for debate. But something has gone seriously off track in how we evaluate dog and cat food, and the people getting it wrong are often the ones who care the most.
When a formula changes, what’s the first question people ask?
- Does it have fillers?
- Are there by-products
What nobody asks:
- What changed in the nutrient profile?
- Did digestibility shift?
- Are there any measurable differences in how dogs are actually doing on the food?
These questions are missing from every conversation. And that absence is doing real harm.
The List of Ingredients
When we’re talking about kibble or canned diets, we are talking about processed food. Some ingredients are processed multiple times. Processing, which includes grinding, cutting, drying, fractionating, heating, and pressure, changes the structure, digestibility, and nutrient availability of nutrients supplied by ingredients. Sometimes in a positive way, sometimes not. That is not opinion. That is established food science.
A kibble is not a list of raw ingredients. It is a formulated, processed diet designed to deliver nutrients in a specific way, and that process is complex and nearly impossible to genuinely simplify. Yet that is exactly what the industry keeps trying to do.
Two foods with similar ingredient lists can have markedly different nutrient profiles, digestibility, and biological outcomes depending on formulation, processing, and nutrient balancing. Conversely, foods with very different ingredient lists can deliver nearly identical nutritional profiles. What complicates this further, is the bioavailability of the nutrients supplied by these foods, or in other words if the pet can use those nutrients or not. This is why companion animal nutrition evaluates diets on nutrient composition and performance, not ingredient appearance alone. When we reduce evaluation to labels, we ignore the actual formulation work that determines how a diet functions in the animal.
“Filler” Is a Marketing Term. Not a Scientific One.
“Filler” and “by-product” are not scientific or regulatory classifications. They have no legal definitions. They are marketing terms, and they have been so thoroughly adopted by the independent retail channel that we now deploy them as if they constitute clinical evidence of poor nutrition. They do not.
Ingredients like starches and fibers that get reflexively dismissed as “fillers” are frequently included for defined functional reasons: stool quality, fermentation, energy delivery, and overall gastrointestinal function. In plain language, they help deliver nutrients the body needs, and without them there are health consequences. That doesn’t automatically make them ideal in every context, but it also doesn’t make them meaningless, inherently low quality, or a filler.
Take beet pulp for example. It is a moderately fermentable fiber used because it reliably supports stool consistency and colonic health. It is well-studied. It has a defined, functional role in processed pet food. The same fiber category shows up in boutique kibbles and raw toppers under names like chicory root, inulin, and pumpkin, where it gets called a prebiotic or a digestive support ingredient. The ingredient optics are just different. Is it the first ingredient I’d reach for when building a species-appropriate fresh food diet from scratch? No. But calling it a filler is not just imprecise. It is wrong. And communicating ingredients like this to pet parents as nutritional evidence of a food’s decline is a problem.
Ingredient lists also do not reflect dose, proportion, or functional contribution. An ingredient included at a physiologically meaningful level is very different from one included for label appeal, yet both appear identically on a panel. Without understanding inclusion rates and functional intent, it is not possible to determine the role an ingredient is playing in the diet. This is a fundamental limitation of label-based evaluation that is never acknowledged.
Facts About Formulation
One of the most overlooked aspects in pet nutrition is that diets are not simply collections of ingredients, but instead formulated systems. Formulation becomes more important as ingredient complexity increases. For example, whole food inclusions can introduce variability in nutrient composition, bioavailability, and balance, particularly after processing. Without careful formulation and post-processing validation, diets can miss targets for essential nutrients despite appearing high quality on paper.
This is well recognized in both human and veterinary nutrition, where nutrient adequacy, not ingredient identity, is the standard for evaluating a diet. If these outcomes are not being considered, the evaluation is incomplete regardless of how the ingredient list reads.
Ask ‘Un-spin-able’ Questions
If a food has genuinely declined in quality, that is a serious claim. It should be supported by something measurable:
- Changes in nutrient adequacy
- Shifts in digestibility
- Safety concerns backed by data
- Clinical outcomes
Without that, what we have is a store philosophy being communicated as nutritional evidence. Those are not the same thing. Conflating them is where this industry keeps losing the credibility it needs with the veterinarians and scientists who should be its allies.
Digestibility: The Forgotten Variable
Not all nutrients that are listed are utilized. Digestibility determines how much of a nutrient is absorbed and available to the animal, and this can vary significantly between ingredients and processing methods.
A diet with a cleaner ingredient list but lower digestibility may deliver fewer usable amino acids or available energy than a more processed diet with an optimized formulation. In clinical settings, highly digestible diets are often prioritized for gastrointestinal disease, recovery, and performance, not because of how the ingredient list reads, but because of how efficiently the animal can use the nutrients provided.
Without considering digestibility, ingredient-based judgments are incomplete.
The Questions We Should Ask
If we are genuinely concerned about the long-term health impact of processed diets, and there are real reasons to be, there are far more scientifically meaningful questions to be asking than whether an ingredient is labeled a by-product.
Advanced glycation end products (AGEs). These compounds form during high-heat processing, including the extrusion process used to produce kibble. Extrusion exposes ingredients to high temperature and pressure, conditions known to drive Maillard reactions and the formation of these compounds. In human nutrition, AGEs have been associated with inflammation and metabolic dysfunction. In dogs, emerging work is beginning to explore similar pathways. Yet these factors are rarely part of how foods are evaluated at the consumer level, despite being a direct consequence of processing itself.
Acrylamide. Also formed during high-heat processing, and with established health risks in human nutrition. Likewise, these are rarely discussed in the pet food retail context.
Antinutritional factors. Ingredients perceived as clean or whole are not inherently superior if they are not processed appropriately. Legumes and certain grains can contain compounds such as phytates, lectins, and protease inhibitors, which can interfere with mineral absorption and protein digestion if not addressed. In human nutrition, these are well-characterized concerns mitigated through soaking, fermenting, or cooking. In pet food, extrusion reduces some of these compounds, but not always uniformly. This raises a more meaningful question than what is on the label: how were these ingredients processed, and did that processing optimize or limit nutrient availability?
These are the questions that would move the needle on long-term pet health outcomes. They are also the questions almost entirely absent from the conversation at the consumer level, the retail level, and in a lot of influencer-driven content that passes itself off as ‘nutrition education’.
The Uncomfortable Reality for the Fresh Food Camp
I am in the fresh food camp. But there is a persistent assumption in this space that whole food or minimally processed ingredients inherently lead to better nutrition, and that assumption warrants more examination than it recieves.
We’ve swung from one extreme to another. For years, the mainstream commercial pet food establishment dismissed ingredient quality entirely. The backlash was warranted. Ingredients do matter. But we overcorrected. We started treating the ingredient list as the whole story, layered marketing language on top of it, and then communicated that to pet parents as if it were grounded in nutrition science. We built a framework where whole food automatically means better and by-product automatically means bad, without any serious consideration of food science, processing effects, formulation complexity, or measurable outcomes.
And then we used that framework to tell people their pets’ food was no longer good.
Flattening that distinction with the word “filler” doesn’t protect pets. It creates confusion, erodes trust, and generates an enormous amount of unnecessary churn for pet parents who are genuinely trying to do right by their animals.
Imagine If We Asked Different Questions?
Focusing on ingredient perception ignores one of the most practical and measurable indicators of diet quality: how the animal performs on the food. Stool quality, body condition, coat quality, and gastrointestinal tolerance are not subjective preferences. These are reflections of how well a diet is being digested and utilized.
Dogs and cats don’t respond to ingredient stories and philosophies. They respond to what the diet does in the body and how processing affects that. In clinical and research settings, outcome variables like digestibility, tolerance, metabolic response, and long-term health markers are the standard for evaluating diet performance. If a diet supports stable body condition, consistent stool quality, and overall health, that reflects functional adequacy regardless of whether the ingredient list aligns with a particular narrative.
Without incorporating outcomes, diet evaluation remains theoretical rather than physiological.
My View:
I am not a champion of ultra-processed food. The evidence for minimally processed and fresh diets, when properly formulated, is compelling and growing. I think we should be moving pet parents in that direction when we can and meeting them where they are when we can’t.
But I am not going to tell a pet parent their dog’s food is no longer good without evidence. I am not going to call beet pulp a filler because it makes for a cleaner story. And I am not going to let this industry keep making pet parents feel guilty or confused about feeding their dogs a properly formulated, nutrient-adequate processed diet because we decided that an ingredient list is more important than actual nutritional outcomes.
None of this is an argument against caring about ingredients. It is an argument for using them correctly. Ingredients are part of the picture. But in processed diets, they are not the whole picture, and in many cases, they are not the most informative part.
The question has to shift from what’s in the food? to what does the food do? Until it does, we will keep generating confusion, eroding trust, and sending pet parents on an endless loop of switching foods based on rhetoric instead of evidence.
That is not advocacy. That is the opposite of it.
