Is Grain-Free Cat Food Better? What the Evidence Says

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

Walk down the cat food aisle and you will see grain-free on many bags and cans. The label suggests a more natural, healthier choice. But is it? The evidence suggests that grain-free is largely a marketing term, and that what matters is the overall quality and balance of the diet.

Why grain-free became popular

Pet food trends follow human food trends. As gluten-free and low-carb diets grew, pet food makers produced grain-free versions. Cats are obligate carnivores that evolved eating prey, so it seemed logical that they would not need grains. Many owners also believe grains cause allergies.

What cats really need

Cats need high levels of animal protein, specific amino acids such as taurine, certain fatty acids, vitamins and minerals. See taurine: why cats need it. They need little carbohydrate, though they can digest cooked starches in moderation. A complete diet meets standards for the cat's life stage. See how to read a cat food label.

Grain-free does not mean low-carb

Many grain-free foods use potatoes, sweet potatoes, peas, lentils or tapioca instead of grains. These can have as many carbohydrates as foods with rice or corn. Some grain-free dry foods contain a lot of starch. To judge carbohydrate content, check the guaranteed analysis and ask the manufacturer. Wet foods generally have lower carbohydrate than dry. See wet vs dry cat food.

Are grains a common allergen?

No. Studies suggest that the main food allergens in cats are proteins, such as beef, fish, chicken and dairy. Grain allergy is rare. If your cat has itchy skin or digestive upset, the cause is more likely a protein, fleas or environmental allergy. See cat food allergies and sensitive stomachs and cat skin allergies. A vet-guided elimination diet is the way to find out.

The heart disease question

In dogs, the US Food and Drug Administration investigated reports of heart disease, specifically dilated cardiomyopathy, in dogs eating certain grain-free diets, often high in peas, lentils and potatoes. A clear cause has not been established. In cats, evidence is limited, and a link has not been proven. Taurine deficiency causes heart disease in cats, so it matters that foods are complete. See hypertrophic cardiomyopathy in cats for the main feline heart disease, which is largely inherited and not caused by diet.

When low-carb diets help

Some diabetic cats do better on low-carbohydrate diets, and may need less insulin. This is due to carbohydrate level, not the absence of grain. A vet should guide any diet change in diabetic cats. See diabetes in cats. Overweight cats may also benefit from controlled portions and higher protein. See how to help an overweight cat lose weight.

How to choose a food

• Look for a statement that the food is complete and balanced for your cat's life stage.
• Prefer foods with animal protein as the first ingredients.
• Consider wet food for water intake. See how to get a cat to drink more water.
• Check calories, and measure portions. See how much should I feed my cat.
• Choose reputable manufacturers who employ nutritionists and run feeding trials.
• Ask your vet about your cat's needs, especially if it has health problems. See best food for senior cats.

What about raw and homemade?

Raw and homemade diets carry risks and must be balanced. See raw food diets for cats.

Switching foods

If you change foods, do it gradually. See how to switch cat foods.

Kittens

Kittens need a food made for growth. See kitten feeding schedule.

Reading the guaranteed analysis

The guaranteed analysis shows minimum protein and fat and maximum fiber and moisture, but not carbohydrate. You can estimate carbohydrate by subtracting protein, fat, fiber, moisture and ash from one hundred percent, or ask the manufacturer for the figure. Comparing dry and wet foods requires converting to dry matter, since moisture differs widely. A vet or nutritionist can help.

Marketing and trust

Words such as natural, premium, ancestral and holistic have no legal definition. Judge a food by its nutritional adequacy statement, the company's testing and your cat's health, not by the front of the bag.

When to see a vet

If your cat has digestive upset, itching or weight changes, see your vet before changing food. Use the US vet directory to find a clinic, and see cat vet visit costs.

This article is general educational information, not veterinary advice. Every cat is different. If your cat is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.