Catster logo

Is It a Cat Food Allergy or Intolerance?

Could your cat have a food allergy … or an intolerance? How do you tell the difference and how do you treat them?

grey vat near food bowl
Image Credit: Pixel-Shot, Shutterstock
Last Updated on December 6, 2023 by Catster Editorial Team

Food impacts all of us in different ways. Some people can develop downright deadly allergic reactions to eating peanuts whereas others may simply incur bloating or abdominal pain when eating a whole-wheat ham sandwich containing gluten. The same holds true for how certain foods impact your cat.

Which brings us to this important feline nutrition lesson: Do you know the difference between a food allergy and a food intolerance in your cat? After all, in both situations, vomiting can occur.

Food allergies in cats vs. food intolerances in cats

A cat itching and scratching.
A cat itching and scratching can point to cat food allergies. Photography ©Axel Bueckert | Getty Images.

To clear up the confusion, Catster turned to two leading experts in feline health: Elisa Katz, DVM, a veterinarian based in the Chicagoland area who serves on the Feline Nutrition Foundation board; and Jennifer Coates, DVM, a veterinarian and author based in Fort Collins, Colorado, who serves on the Pet Life Today advisory board.

They explain that a genuine food allergy is a specific type of reaction by the body to an allergen, usually a protein in the cat food. In some instances, the reaction can be severe and even life-threatening if left untreated.

“In essence, the immune system misidentifies a protein as a foreign invader, like a germ, and attempts to fight it off,” Dr. Coates explains. “Certain types of white blood cells, called plasma cells, produce IgE antibodies, which, in turn, attach to mast cells that then release histamine and other substances that result in an allergic reaction.”

A food intolerance, while unpleasant for your cat, is not life-threatening and tends to take aim at the digestive system, causing gas, diarrhea, abdominal cramps and bloating. A key clue that it might be an allergic reaction to a specific food and not simply a food intolerance is to take note if your cat is starting to itch and scratch a lot. “A cat with food allergies may develop scabs from the scratching, loss of fur from constant licking and even have red bumps on his face, ears and abdomen,” says Dr. Katz, who operates Holistic Veterinary Center in Downers Grove and Bourbonnais, Illinois.

Some cats can be severely allergic to vaccines, shellfish or insect stings. The body reacts by going into anaphylaxis or shock, plummeting the blood pressure, causing difficulty breathing, loss of bladder/bowel control and even collapsing into unconsciousness. This is an extreme emergency that needs immediate veterinary care to save the cat’s life.

Both experts agree that any cat at any age can develop both food allergies and food intolerances.

“While genetics does seem to play a role in determining which cats develop food allergies, a definitive list of high-risk breeds isn’t available,” Dr. Coates says. “That said, the Siamese is often cited as being more commonly diagnosed with food allergies than other breeds.”

What can you do about cat food allergies or intolerances?

As to specific proteins that may trigger allergic reactions, a veterinarian study published in 2016 identifies the top two culprits for cats as being beef and fish, followed by chicken, wheat, corn, dairy products and lamb.

Dr. Katz suspects that vaccines may disrupt the immune system and may play a role in why some cats develop food allergies later on in life.

Both encourage pet parents to scrutinize food ingredients on packaging and be on the lookout for terms like “natural” flavor as well as artificial colors or chemical preservatives, such as BHA and BHT.

“Read the whole list of ingredients before making a healthy choice for your cat,” Dr. Katz says. “Look for quality ingredients, such as real meats and not chicken meal, which is not a good protein source. The term ‘natural flavor’ is nutritional gobbledygook.” Other recommendations to fortify your cat’s digestive health? Ask your veterinarian about the possible benefits of supplementing your cat’s diet with omega-3 fatty acids and digestive enzymes with probiotics.

For cats with confirmed allergies, it is vital to work closely with your veterinarian to select diets that will not enhance the allergic reaction. Dr. Katz suggests gradually switching your cat from commercial “cooked” dry and canned diets to a commercial raw food diet now available in freeze-dried, pre-packaged frozen and dehydrated varieties that you add water to. Be patient. It takes time to identify the cause of your cat’s response to certain foods. Your veterinarian will also advise you as to how long your cat needs to stay on a special diet.

“As you can see, food allergy and intolerance are much more complicated than they may first seem,” Dr. Katz says. “Work closely with your veterinarian, and with patience and diligence, you should be able to find out what is afflicting your cat.”

Elimination diets for your cat’s food allergies / intolerances

A cat eating out of food bowls lined up.
How do you find out what your cat is allergic / sensitive to? Photography ©Serenethos | Getty Images.

Your cat may show outward signs that some food is not agreeing with him, such as weight loss, vomiting and itching, but he certainly can’t tell you the specific food culprit. That’s where it may be necessary to work with your veterinarian and put your cat on what’s known as an elimination diet. “An elimination diet is a way of determining what foods a cat is allergic or sensitive to,” says Dr. Jennifer Coates.

“During an elimination diet, a cat should eat a food that avoids common food allergens and is made with a single protein source that the cat has never eaten before or that has undergone hydrolysis (a process that breaks proteins down into such small pieces that they are ignored by the immune system).”

That means no table scraps, no treats and no flavored medicines for your cat. And make sure he is not trying to steal food from other cats in your household.

“It is so frustrating to go through all the work involved in an elimination diet only to have the results spoiled by something that should be preventable — like feeding table scraps to your cat,” she adds.

In addition to feeding your cat a single protein diet, your veterinarian may also take a blood sample to analyze your cat’s white blood cells as well as possibly do a saliva test. “The number of white blood cells can give us a clue if we are dealing with an allergy,” Dr. Elisa Katz says. “Saliva tests are more done for detecting food intolerances as they focus on what is within the gut.”

Read more about cat food on

Feature Image Credit: Pixel-Shot, Shutterstock

About the Author

Arden Moore
Arden Moore
Arden Moore, The Pet Health and Safety Coach, is a pet behavior consultant, master certified pet first aid instructor, author and host of two shows: Arden Moore’s Four Legged Life national radio show and a podcast called the Oh Behave Show on Pet Life Radio. Learn more at

Get Catster in your inbox!

Stay informed! Get tips and exclusive deals.


Follow Us

Shopping Cart