Finding the Right Pet Food

Dr. Cassie Knapp

Veterinarians are just as confused as pet owners by pet food marketing, and there is a lot of misinformation and mythology on the Internet regarding pet food. In particular, guilt-based or emotion-driven marketing and propaganda should be viewed with skepticism, especially when it is used to sell expensive pet food. -RR

Veterinarians should be the point of reference and clarity for pet owners concerning pet food selection. -RR

3 Common Myths – taken from AAHA January 2017

  1. Dogs and cats did not evolve eating grains and therefore cannot digest grains.
  • A 2013 study by Swedish geneticist Erik Axelsson reported in the journal Nature that “in a domestic dog’s vs. wolf’s genome comparison, three genes responsible for the digestion of dietary starch were expressed at 7-12 fold higher levels in the dog compared with the wolf.”
  • Digestibility studies published in the Journal of American Physiology and Animal Nutrition have demonstrated that dogs and cats digest better than 95% of the starch in a properly cooked diet containing 50% corn or rice.
  • The digestibility of a given nutrient is what matters.
  1. Corn and other grain sources of protein are non-nutritive fillers
  • Botanically speaking, corn is no different than any other grain in its main composition. However, when its more intact levels are included in the diet, its protein digestibility can go down.  Think what happens after you (or your dog) eat an intact kernel of corn…  As a grain, corn has a biological value of 74. This is just a measure of the amount of essential amino acids (AA) within a food. You may remember that essential AAs are the building blocks of life. Compare 74 to muscle meats (beef, chicken) which score around 75 and egg, which scores 100.
  • All plants, due to their cellulose layers, have decreased digestibility when compared to meats. But when ground and cooked to break up those layers, plant digestibility increases. Think what happens when you (or your dog) eat a corn tortilla.  When corn is combined with other plant products, it can achieve a score of 100, as well.
  • The claim that corn is no more than a filler is simply misinformation. Depending on how grains are processed, they can be highly digestible. Some contribute dietary fiber to pet foods, which is a nutrient that plays a vital role in intestinal health and stool quality.
  • Although grain-free diets can provide optimal nutrition for cats and dogs, diets containing grain can do the same.
  1. Grains are allergenic
  • At this time there is no evidence to support that animals on grain-free diets have less incidence of food allergies than animals on conventional diets.
  • Wheat gluten is unique in how large its protein structure becomes when its AA building-blocks are folded-up, meaning it would be the most likely grain to trigger an allergic reaction. Wheat gluten ranks 5th (tied with chicken) as a pet food allergen.
  • Currently, the most common food allergies are beef, dairy and egg.

Quotes taken from Rebecca Remillard PhD, DVM, DACVN, Ann Wortinger BIS, LVT (ECC, SAIM, Nutrition), Martha G. Cline DVM, DACVN and Jennifer Larsen DVM, PhD, DACVN

Ingredient Label Tricks: Splitting – March 2014


Pet food labels are required to list ingredients in order of their prominence by weight within the food. The weights are determined “as is,” meaning as they are added into the formulation, including their inherent water content.

Sometimes lists can be deceiving because lower quality ingredients can be ‘split’ on the label so their contribution to the food appears to be less than what it actually is while simultaneously improving the position of higher quality ingredients.

Here’s an example:

Chicken meal, ground whole wheat, wheat flour, corn gluten meal, ground rice, rice bran, chicken fat

Although chicken meal is 1st, notice that a form of wheat is both 2nd and 3rd and that a form of rice is both 5th and 6th – now, if you added the wheat and rice ingredients together, the list would look different:

Wheat, rice, chicken meal, corn gluten meal, chicken fat

Not quite the same story, especially if you’re looking for a food with a protein as the 1st ingredient. What appeared to be a predominantly meat-based food now looks more like a grain-based food.

Understanding a pet food bag and a label


  • What wording is used on the front of the bag? If Holistic, Human-grade, Premium, Super-premium or Ultra appear on a bag– you need to ignore them. These are non-regulated words, which means they are open to interpretation not only by you, the consumer, but also by the manufacturer. They have no meaning with respect to nutritional value and are printed on a bag to appeal to a particular audience. That’s not right or wrong; that’s marketing— just don’t be influenced by the presence or absence of one of these words. They should never influence your decision-making.
  • Are the pictures what’s drawing you in? Images of whole pea pods, chicken drumsticks or a swimming salmon may give you an idea of what’s in the food, but recognize that these “whole” ingredients don’t exist within the bag in the form that’s conveyed on the bag. These ingredients are mechanically ground down and chemically broken apart via some combination of rendering, processing and dehydration before making it to your pet.

The desirable filet cuts of meat are being shipped out for us humans to consume, not our pets. This isn’t wrong or bad, as there are still extremely nutritious parts of the food-producing animal; it’s just that these are often designated for pet consumption because they’re not socially or culturally acceptable for humans to eat. When evaluating a bag of food— to walk away with the assumption that a pure, unadulterated form of that swimming salmon is inside your bag is a misdirection, and often a costly one.

  • What is the brand? Only 3 brands use research-based clinical feeding trials to make an ingredient list. (The alternative essentially involves feeding an ingredient profile to a computer and analyzing if the data meets daily nutrition requirements.)  Combined, these 3 organizations employ thousands of veterinarians, nutritionists and scientists to create pet foods that go beyond a “complete and balanced” formula. They create the highest quality, most meticulous diets that are both therapeutic for our sick patients, and preventative for our healthy ones.  These are Hill’s, Royal Canin and Purina (ProPlan and Veterinary Diet labels) – that’s it.
  • What is the ingredient list? Have they split up starches or grains into multiple ingredients to make one component (i.e. meat) look larger and another smaller?


  • If farm fresh produce is being promised on the bag, do these show up after “sodium chloride” (a.k.a. table salt) when listed out on the label, indicating there’s more salt in the food than fruits and vegetables? That could be quite misleading.
  • If the bag claims to be limited ingredient, is there more than 1 protein source (e.g. rice, oat, barley, chickpea, wheat, corn, pea, lentil) in addition to the meat component? If so, then it’s not “limited” after all—what makes something “limited” is the use of a single protein source to limit the chance of causing a food allergic reaction.
  • Does it say “by-product” or “by-product meal” next to any of meats? That’s not an issue.  Surprised?  Don’t be.  “By-product” and “meal” are terminologies long ago made and defined by government regulatory agencies. Yes, they sound awful. Yes, it would be nice if they re-worded those, but recognize that horrible wording aside—they encompass nutritionally-rich components (albeit unsavory to most human palates) of a food-producing animal. These food sources are protein-rich and highly digestible when cooked properly.
  • Does it say organic? Again, it’s not right or wrong. Organic is a government-regulated term that refers to the way a food is grown or produced. What it doesn’t do is refer to or affect the nutritional value of the food.  Some of the highest quality pet foods we have available undergo and pass rigorous safety testing but are not organic.
  • If something is claiming to be “natural,” is there a list of difficult-to-spell-or-pronounce synthetic vitamins and minerals at the end of the list? Synthetic vitamins and minerals are fine— humans take them as supplements every day— but to advertise that particular food as “natural” would be misleading. Although a regulated word (as is organic), “natural” does not translate into: the quality of the ingredients, the purity of the ingredients or the product, any special manufacturing of the product, any research behind the product or any specific “health benefits” even if it’s in the Product Name.
  • Does it say grain-free? Again— not right or wrong, but remember that grains contain many nutrients that are digestible by the body when properly processed and cooked. Think intact corn kernel vs. corn tortilla. Plus, grains are about as straight-out-of-the-earth as you can get.


Takeaway Points

  • Domesticated dogs, cats have genetic adaptations to utilize starch better than their ancestors
  • Grain is a good source of digestible nutrients
  • Corn is a grain
  • Wheat gluten can be allergenic due to its complex molecular structure and larger size



__ Any ingredient splitting, to make a label appear more desirable to a consumer?

__CROSS OFF THESE WORDS: holistic, human-grade, premium, super-premium, & ultra, which are marketing terms with NO nutritional significance

__ CROSS OFF “Natural,” as these products still contain 6-10% synthetic vitamins and minerals

__ Look beyond the graphic design & pictures on the bag: they’re only marketing, not nutrition

__ What’s the brand? Only 3 use science-based feeding trials: Hill’s, Royal Canin, Purina ProPlan

__ Do any fruits, veggies, or grains get listed after sodium chloride (salt)? If so, there’s more salt in the bag than fresh produce!

__ Are by-products and/or by-product meal on the label? That’s fine – they’re great sources of digestible protein and minerals

__ BE AWARE: diets claiming to be limited-ingredient often include > 1 protein source; how many do you count?