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Written by leading veterinarians to provide you with the information you need to care for your pets.

Your dog's nutrition is important for a healthy & happy life. petMD experts help you to know what to feed your dog, how much food to feed, and the differences in dog foods, so your dog gets optimum nutrition.
Nutrition Nuggets is the newest offshoot of petMD's Dog Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of dog nutrition.

How to Compare Pet Food Nutrient Profiles: Part 2

January 08, 2016 / (2) comments

Last week we talked about how veterinarians typically compare the nutrient profiles of pet foods. It involves a lot of math, conversions, and some estimation… not ideal, to say the least. Today, let’s look at another method. It’s a relatively new approach (at least for me), but is a bit more user-friendly.


No matter what type of food you offer, your goal is to provide the number of calories necessary to maintain a healthy body weight. So, let’s say you are switching your 60 pound, neutered dog from a dry to a canned food with the primary purpose of increasing his protein intake. He is currently taking in 1400 calories a day and he is still going to need 1400 calories worth of his new food to maintain his weight despite the fact that the volume and weight of his meals are going to change dramatically.


Dr. Justin Shmalberg, Diplomate ACVM, describes how we can compare foods on a per-calorie basis:


Step 1 – Add 1.5% to the protein percentage and 1% to the fat percentage from the pet food label

Step 2 – Divide kcal/kg by 10,000 (also on the label)

Step 3 – Divide estimated protein % and fat % by number obtained in Step 2 to get the result in grams/1000 kcal


Here’s an example of how it works. Let’s compare the protein percentages of Dry Dog Food A and Canned Dog Food B.


Dry Dog Food A

3589 kcal/kg


Crude Protein, minimum


Crude Fat, minimum


Crude Fiber, maximum


Moisture, maximum



Canned Dog Food B

960 kcal/kg


Crude Protein, minimum


Crude Fat, minimum


Crude Fiber, maximum


Moisture, maximum



Using the steps outlined above…


Dry Dog Food A


Step 1 – 24% + 1.5% = 25.5%

Step 2 – 3589 / 10,000 = 0.3589

Step 3 – 25.5 / 0.3589 = 71 g protein/1000 kcal


Canned Dog Food B


Step 1 – 8% + 1.5% = 9.5% protein

Step 2 – 950/10,000=0.095

Step 3 – 9.5 / .095 = 100 g protein/1000 kcal


Therefore, the canned food in this comparison is significantly higher in protein than is the dry.


You’ll still have to calculate the estimated carbohydrate percentage of any pet foods you are interested in since this number does not have to be reported on the label. See last week’s post to learn how to do this. Once you have that information in hand, you can use steps 2 and 3 to compare the carbohydrate percentages of different foods.


Handy, eh?


Dr. Jennifer Coates




Shmalberg, DVM, Diplomate ACVN. Beyond the Guaranteed Analysis, Comparing Pet Foods. Today’s Veterinary Practice. January/February 2013.

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... graduated with honors from the Virginia-Maryland Regional College of Veterinary Medicine in 1999. In the years since, she has practiced veterinary medicine in Virginia, Wyoming, and Colorado. She is the author of several books about veterinary medicine and animal care, including the Dictionary of Veterinary Terms, Vet-Speak Deciphered for the Non-Veterinarian .

Jennifer also writes short stories that focus on the strength and importance of the human-animal bond and freelance articles relating to a variety of animal care and veterinary topics. Dr. Coates lives in Fort Collins, Colorado with her husband, daughter, and pets.