Grain-free Cat Food – What Does It Mean?

So, yes, we should seek grain-free foods for our cats, but a “grain-free” designation is just a starting point for good cat nutrition.

Why grain-free food for our cats?

Written by Laurie Goldstein - This article reflects Laurie's personal views on cat nutrition.

Cats are Obligate Carnivores.

That means they are an animal that has evolved to derive all of their needed nutrition from only eating other animals.

Cats were domesticated by ancient farmers who valued their ability to hunt rodents.

As agriculture developed in the Middle East, cats became an invaluable partner to humans.

Cats weren’t eating the grain: they were eating the animals that did.

And things have not changed.

According to the PetMD website, 'domesticated', our pets have not evolved rumens along their digestive tracts in order to ferment cellulose and other plant material, nor have their pancreases evolved a way to secrete cellulose to split the cellulose into glucose molecules, nor have dogs and cats become efficient at digesting and assimilating and utilizing plant material as a source of high quality protein. Herbivores do those sorts of things.

A Short History of Grain-Free Marketing

Cat eats dry food from a large bowl

While some high protein diets existed prior to the introduction of "grain-free" foods, the average dry pet foods contained just 18% - 24% protein, with up to 75% carbohydrates.

In many dry foods, the bulk of the protein came from non-animal sources like corn or soybeans.

These diets may have met AAFCO's minimal nutrient requirements but they were far from ideal nutrition for carnivores, let alone our little purring predators.

After the introduction of the first grain-free pet foods, the ratio of protein-to-carbohydrates changed.

Grain-free diets were typically formulated with 30% or more animal-based proteins and far fewer carbohydrates.

The characteristic that originally made grain-free kibble unique was the higher level of protein, derived from carnivore-appropriate animal ingredients.

While some cats may have “allergies” to grains (or develop them), it is the high animal-based protein, low carbohydrate ratio that should be a primary focus when searching for the healthiest option for our cats.


So why is grain-free just a starting point in identifying a healthy cat food?

Owner feeding cute cat at home

Grains are indeed a chief culprit when it comes to carbohydrates, but cat food manufacturers get away with being able to market a "grain-free" food that still has too many carbs.

They do this by adding legumes and other plant-based ingredients that are not derived from grains.

Why do they do that? Cost, plain and simple.

Meat and meat by-products cost more than plant-based ingredients. Cat food needs to be affordable, and companies want to make a profit.

Cat food can be labeled “grain-free” yet still contain a high level of carbohydrates.

Whether that starch comes from corn (a grain) or soy or peas (legumes), it increases the carbohydrate content of the food.

Some pet food companies increase their profit margin by riding the “grain-free” marketing wave without actually providing food that is carnivore-appropriate.

An analysis of cat food conducted in 2012, covering 48 different types of kibble (including 19 “grain-free” formulas of dry food), 40 brands of canned food (including 16 “grain-free” formulas), and 13 brands of commercial raw cat foods made it quite clear that the consumer cannot rely on “grain-free” to mean carnivore-appropriate.

Bear in mind, the natural diet of a cat contains just 2.8% carbohydrates.

high angle view of pet owner holding two food bowls with wet food. Two hungry cats are sitting on the floor waiting looking up

Dry Foods:

  • The average carbohydrate content of the 48 dry food brands was 27.8%
  • The average carbohydrate content of the grain-free kibble was 22.4%
  • The dry food brands not marketed as grain-free ranged from 22% carbs to 43%
  • The grain-free dry food brands ranged from 7% carbs to 42%

Canned Foods:

  • The average carbohydrate content of the 40 canned food brands was 13.1%
  • The average carbohydrate content of the 15 grain-free canned foods was 12.5%
  • The canned food brands not marketed as grain-free ranged from 2% carbs to 30%
  • The grain-free canned food brands ranged from 2% carbs to 22%

Raw Foods:

  • The average carbohydrate content was just 2.7%
  • The commercial raw food brands ranged from 0.5% carbs to 8%

thief cat to filch food of kitchen table. the cat wants to steal a piece of meat

As you can see, quite a few of the grain-free foods have carbohydrate content that is significantly higher than that recommended for cats.

So “grain-free” is a good starting point in identifying foods appropriate for our cats: but the designation alone is not enough to determine if the food provides their optimal nutrition.


Written by Laurie Goldstein
Laurie Goldstein is a CFA Charterholder. In addition to her work as an equity analyst, she applies her research skill to all things cat, focusing on nutrition and advocacy for feral cat management via trap-neuter-return (TNR) and educational research on cat predation. Learn more about feral cats on her website Stray Pet Advocacy.

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12 comments on “Grain-free Cat Food – What Does It Mean?

Morehappawness March 16, 2022
Perfect, Thank you for this
morehappawness February 21, 2022
Thanking you for this article, because anything that helps our cats is a good thing.
reena ronald February 9, 2014
Thanku......great cat was straining in the litter box since yesterday and passing semi fluid I know what caused it I feed her a commercial grain free meal yesterday...Thanku have put my mind to rest.I was so worried.... :)
angels mommy January 29, 2014
Great article Laurie. Next month It will be 1 yr. that Angel has been on the Purina UR SO canned Rx food.  I am going to ask the vet about starting to maybe cut it 1/2 & 1/2 W/ the Before the Grain that he used to eat, to help cut the carbs. in the Rx food!  Not only will this be better for him, but hopefully, he will finally loose a lb or two.  I would love to see a thread started as suggested above, to compare brands. I used to feed Angel Before the Grain, or By Nature. Both are 95-96% protein, & no by products! :)
Anne January 21, 2014
@Susan Cannon please see my reply above :) You can find recommendations in our cat food reviews section and also by searching the nutrition forums or starting a thread there.
Anne January 21, 2014
@jenpriester  these things change, so it's best to start a thread about this in the cat nutrition forums
jenpriester January 21, 2014
What brands do you recommend?
susan cannon January 17, 2014
Been about 2yrs. now since my cat has had any urinary tract health problems. She is eating both the dry, and the wet Hills c /d Prescription Diet for urinary tract health. Does she have to stay on this for the rest of her life? Could I just try regular cat food again? The reason I ask is have 10 cats, and they all eat it, would like to economize. A bit pricey for 10. Any suggestions.....?
betsygee January 10, 2014
Yes, I've had a couple of vets pretty much try to convince me that my cats will die if I don't buy the food they sell at their practice.  Okay perhaps I'm exaggerating a bit LOL but they can get pushy about it.  My vet was like yours, Maureen--she has cans of something on her shelf for sale, I didn't even notice what, but she talked about other foods to try.
maureen brad January 10, 2014
Be careful with the vets. To many of them will sell you on the foods the market like Science diet. Mine sells Science Diet but has never recommended it to me she talks about other foods. I wonder if it is her partners that sell the SD.
ldg January 9, 2014
Perfect! I hope things went well.
betsygee January 8, 2014
Thank you for this, Laurie!  The timing couldn't have been more perfect. I got on the computer this morning intending to look up information about the importance (or not) of grain-free food for cats.  I have a meeting with a new vet this afternoon and wanted to have an informed conversation about what's the best food for my cats.  Your explanation about carbohydrate content is just what I needed to know.  

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