Judging pet foods


A dizzying array of pet foods are available in grocery stores, pet supply stores, and pet food boutiques. Many of these pet diets are high-quality foods backed by nutritional research and quality control testing. But some may not be! Not all pet food makers have a high level of nutritional expertise and quality control. And while some pet foods may be just as nutritionally sound as other foods, they may be priced out of reach, perhaps only because they include tiny amounts of ingredients that sound tasty to you, yet they add no nutritional value for your pet. So how do you assess which options are right for your pets and your budget?

Alluring labels

Pet food labels primarily serve as eye-catching advertisements designed to entice pet parents. So beyond the glamor and emotional appeal of the label, pet parents frequently turn to a food’s ingredient list to assess a diet’s quality. But did you know? The ingredient list offers only limited information about the nutritional value and quality of a pet food.

Ingredients and water weight

One of the biggest reasons it’s challenging to judge a food by its ingredient list is that the ingredients must be listed on the label in descending order according to their weight, which means each ingredient’s water content counts. And although water is an essential nutrient necessary for life, water doesn’t provide most other nutrients needed to sustain life, and water can typically be obtained for less cost outside of a pet food. 

For example, meat such as chicken, beef, pork, and fish each contain about 70% (or more) water. So a pet food that lists beef as the first ingredient may actually contain less beef than a food that lists beef meal (which contains only about 10% water) as the third ingredient. So keep in mind that ingredients listed first on the label don’t necessarily contribute the most nutrients to that food.

Based on water content, you might also be tempted to think that canned foods are less nutritious than dry kibble, simply because they contain a lot of water, and water is often listed as the first ingredient. But to accurately assess the nutrients in dry kibble vs. canned foods, you must compare them on a “dry matter basis.” 

For example, kibble is about 10% water and 90% dry matter. Canned food is about 25% water and 75% dry matter. So based on dry matter, a kibble that lists a minimum of 25% protein in its crude analysis actually contains 27.8% protein (25% protein divided by 90% dry matter, then multiplied by 100). And a canned food that lists a minimum of 10% protein in its crude analysis actually contains 40% protein (10% protein divided by 25% dry matter, multiplied by 100). Yet on quick glance at the crude analysis on each label without doing the math, the kibble appears to contain more protein than the canned food.

Some pet foods include fruit, vegetable, or other whole foods only to make the diet sound especially yummy to pet parents. These ingredients may present in such tiny amounts (veterinary nutritionists at the Cummings School of Veterinary Medicine at Tufts University refer to these amounts as “fairy dust”) that they’re listed on the label after salt or other mineral and vitamin supplements and contribute little, if any nutrient value, but they do add expense. 

Comparing calories

To make things more complex, in order to accurately compare nutrients between pet foods, you also need to factor in the calorie content of each diet on an “as fed” basis. And calorie content isn’t always on the label, so you may have to visit the manufacturer’s website, or call them to get it. Once you have calorie information, pet food nutrient calculators, such as this one https://vetnutrition.tufts.edu/2017/08/nutrient_converter/

are available to help out.

Words that matter

At a minimum, and instead of reading only the ingredient list, look for the American Association of Feed Control Officials (AAFCO) statement or the Nutritional Adequacy statement on the label. It’s usually in small print on the side or back of the package. An AAFCO adequacy statement lets you know that the diet is complete and balanced. So any over-the-counter diets that you select for your pet should have this statement. The statement looks like this:

“(Product Name) is formulated to meet the nutritional levels established by the AAFCO (Dog or Cat) Food Nutrient Profiles for (Life Stage).” Or:

“Animal feeding tests using AAFCO procedures substantiate that (Product Name) provides complete and balanced nutrition for (Life Stage) of (Dogs or Cats).”

Another type of AAFCO statement says “This product is intended for intermittent or supplementary feeding only.” Such a statement can be acceptable on veterinary therapeutic diets because they’re formulated for pets with specific diseases and they’re intended to be fed in accord with a veterinarian’s instructions. This statement is also acceptable for treats that aren’t intended to be fed as a sole diet, because treats aren’t intended as a complete and balanced diet. This statement doesn’t mean that veterinary therapeutic diets aren’t any more nutritious than treats are, it simply means that a therapeutic diet isn’t intended to be fed long-term as a sole diet for a pet that doesn’t have the medical condition that the diet has been specifically formulated to address. 

Digging deeper

You can also check into the quality control protocols of the pet food manufacturer. This information isn’t always readily available on the label, so you’ll probably need to research the company yourself. Important points to consider? Pet food makers should:

  • own their own manufacturing plants, 
  • have certified quality control procedures, 
  • test their ingredients and end products for appropriate nutrient content, 
  • test their ingredients and end products to ensure that harmful bacteria or fungi (or toxins produced by these organisms) aren’t present,
  • employ one or more veterinary nutritionists or PhDs in animal nutrition, 
  • test their diets in AAFCO feeding trials, and 
  • be happy to answer your questions about their food’s nutrient and caloric content. 

An organization called Pet Food Alliance compiled some of this information and provides a handy comparison tool for some pet foods (not all manufacturers responded to include their information) at: https://petnutritionalliance.org/chart/index.php/manufacturer-report.

Learn more about how you can help your grey muzzle dog eat better and feel better, and keep track of meals and treats. 

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Freeman LM. Questions you should be asking about your pet’s food. Cummings Veterinary Medical Center at Tufts University website. December 19, 2016. Accessed January 7, 2022. https://vetnutrition.tufts.edu/2016/12/questions-you-should-be-asking-about-your-pets-food/

Clinical Nutrition Team. Why you shouldn’t judge a pet food by its ingredient list. Cummings Veterinary Medical Center at Tufts University website. June 21, 2016. Accessed January 7, 2022. https://vetnutrition.tufts.edu/2016/06/why-you-shouldnt-judge-a-pet-food-by-its-ingredient-list/

Clinical Nutrition Team. Pet Food Calculator: Comparing nutrient levels between two pet foods. Cummings Veterinary Medical Center at Tufts University website. August 7, 2017. Accessed January 7, 2022. https://vetnutrition.tufts.edu/2017/08/nutrient_converter/

Additional resources

The Savvy Dog Owner’s Guide: Nutrition on the Internet


The Savvy Cat Owner’s Guide: Nutrition on the Internet