The Importance of Protein in Your Cat's Diet: A Guide to Calculating Protein in Commercial Cat Food

As obligate carnivores, cats require a diet high in animal protein. Although this is not disputed, pet food companies often use plant based proteins to supplement animal products. Evaluating the ingredients and percentage of protein can help you decide whether a particular food is a good option for your cat.

My cat, Josh, loves a high animal protein diet. Here he's eating Fancy Feast Classic Pate (turkey) along with Weruva's Green Eggs & Chicken.

Protein is a key ingredient for your Cat's health

According to the Cornell Feline Health Center, "Cats are obligate carnivores, which means that they rely on nutrients found only in animal products. Cats evolved as hunters that consume prey that contains high amounts of protein, moderate amounts of fat, and a minimal amount of carbohydrates, and their diet still requires these general proportions today. Cats also require more than a dozen other nutrients, including vitamins, minerals, fatty acids, and amino acids."

Feral cats show us felines consume 52% protein in their diet

A paper published by Cambridge Univeristy Press in October 2011 reviewed 27 studies of feral cats food consumption evaluating what nutrient composition feral cats select for themselves. "The results show that feral cats are obligatory carnivores, with their daily energy intake from crude protein being 52 %, from crude fat 46 % and from N-free extract only 2 %." When you look at what is in cat food, you often see a lot of variety from product to product of the nutrient composition, which seems odd to me.

My point of view is to trust the cat's natural instinct to know what they need for their food. I have a distrust for large corporations who are profit driven, which is why I often question what the pet food industry wants me to feed my cat.

Animal products vs. Plant-based proteins

Companies are required to list the protein content. However, they are not required to differentiate between proteins derived from animals in the products and protein derived from plant-based products such as soy, corn and wheat.

Veterinarian Lisa Pierson argues that there's a big difference in quality between those two types of proteins. In her article, Feeding Your Cat: Know the Basics of Feline Nutrition, she explains the difference, "Proteins derived from animal tissues have a complete amino acid profile. (Amino acids are the building blocks of proteins. Think of them as pieces of a puzzle.) Plant-based proteins do not contain the full complement (puzzle pieces) of the critical amino acids required by an obligate carnivore. The quality and composition of a protein (are all of the puzzle pieces present?) is also referred to as its biological value." The plant-based proteins are lower in biological value for cats.

Terri Grow, feline nutritionist, explains in her article, Feline Diets: How Food Composition and Processing Can Affect Health and Behavior published in July 2024,

"Today’s cats are fueled by commercial foods formulated with ingredients more for omnivores claiming to address everything from balanced nutrition, shiny fur, and a healthy gut to high energy, healthy weight, immune support, stress, and more. Then why the prevalence of health and behavior issues?"

Surviving vs. Thriving

Some argue that cats adapt to plant-based protein. They may not starve, but are they thriving on the diet? I want cats to thrive, not just survive. The problems I see in my feline behavior practice that stem, at least partially, from nutrition issues include obesity, pica, and predatory aggression. I think Terri Grow is on to something. Some commercial cat foods may not actually be designed for carnivores and as a result, impact our cat's health and behavior negatively.

Why are companies even using plant-based proteins for cats? Dr. Pierson explains, "Because plant proteins are cheaper than meat proteins, pet food companies will have a higher profit margin when using corn, wheat, soy, rice, etc." In 2024, the sales from pet food reached $65.8 billion dollars from food and treats in the United States, according to Petfood Industry. I'd love to know how much of that is profit.

Read the Food Label

The labels can be intimidating. But, we can simplify it. It's the best way to determine if the protein content is adequate.

STEP 1: Look at the Ingredient List

Look at the ingredients to get an idea of whether the protein is going to be animal products or plant-based. I don't necessarily look at every ingredient, but I check the first 5 ingredients which is going to make up the majority of the food. You'll get a good idea if there's going to be a lot of animal product, or whether it's being supplemented with plant-based proteins.

STEP 2: Look at the Guaranteed Analysis

The guaranteed analysis is just below the ingredient list which is going to list the protein, fat, fiber and moisture content. The moisture content can make it confusing in terms of how much protein is actually in the food, so you want to convert it to dry matter which is not complicated.

STEP 3: Convert to Dry Matter - don't be intimated, this is actually easy

High protein budget friendly canned cat food

EXAMPLE: FANCY FEAST CLASSIC PATE TURKEY

Let's look at a popular cat food and figure out the quality and quantity of animal protein: Fancy Feast Classic Pate Turkey. Since the labels are tiny, I often look at Chewy's website to get the breakdown. Scroll down to the ingredients.

Chewy's website makes finding the ingredient list and guaranteed analysis easy. They often list it and have pictures from the manufacturer.

The first 5 ingredients are: turkey, meat by-products, liver, turkey broth and fish. I don't see any plant based proteins here. Although I don't love the ambiguity of "meat by-products" since that could be just about anything, we at least know it's probably protein and it's definitely from animals. The rest are clearly animal products.

Let's look at the Guaranteed Analysis just below the list of ingredients:

Protein 11%

Crude Fat 5%

Crude Fiber 1.5%

Moisture 78%

It's time to do Math, but it's easy Math

1. To convert to a dry matter basis, first subtract the moisture # from 100.

100 - 78 = 22

2. Take the protein % (here it's 11%) and divide by the dry matter moisture # (22). Add a period before the dry matter moisture # which will give us the % in the food.

EQUATION: 11 / .22 = 50

Fancy Feast Classic Pate Turkey contains 50% protein on a dry matter basis, which is very close to what cats would select themselves based on the analysis of the nutrient composition studies of feral cats showing cats eat prey with 52% protein. For my cats, I look for cat food with at least a 50% protein content. Ding Ding Ding, we have a winner!

I'm concluding that this budget friendly food has an appropriate amount of protein for cats and it's derived from animal based products, not plant-protein.

With practice, looking at the ingredient list and converting the protein % to dry matter becomes second nature.

I hope this blog post motivates you to take a closer look at the quality and amount of protein you feed your feline friends. There's a lot to feline nutrition, but focusing on the amount and quality of protein in commercial food is a big step towards giving cats a species appropriate diet.

Check out my Favorite Products for recommendations on cat products.

About the author: Jennifer Van de Kieft, CAFTP, FFCP, PNCC is located in Brooklyn, NY. She is certified in feline behavior and pet nutrition. She owns Cat Advocate, a feline behavior consulting company. She provides cat guardians with the strategies, tools and knowledge needed to address their cat's behavior issues. Jennifer provides virtual consultations throughout the United States.