How Much Protein Do Cats Need? Requirements, Sources and Special Cases

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

Of all the nutrients a cat needs, protein is the one that sets cats apart from most other pets. They need more of it, they cannot do without certain amino acids from animals, and they burn it for energy. Knowing how much, and what kind, helps you read a label and choose a diet wisely.

Why cats are protein specialists

Cats evolved eating small prey that is high in protein and fat, and very low in carbohydrate. Their metabolism reflects this. Their livers constantly break down amino acids for glucose, even when they eat little protein, so they have a high minimum requirement. They also cannot make certain nutrients, and must get them from animal tissue. See taurine: why cats need it.

Essential amino acids

Cats need about eleven essential amino acids from food, including arginine, taurine, methionine and others. Arginine is critical: a single meal without it can cause toxic ammonia buildup. Taurine is needed for the heart, eyes, digestion and reproduction. These are found in meat, fish and organs. Plant proteins are lacking in some of them, so vegetarian diets for cats are unsafe unless carefully supplemented, and are not recommended by most vets.

How much is enough?

Nutritional guidelines, such as AAFCO's, set minimum protein levels:

• Adult maintenance: at least about 26 percent of calories from protein, or about 6.5 grams per 100 kilocalories.
• Growth and reproduction: at least about 30 percent of calories, or 7.5 grams per 100 kilocalories.

These are minimums, to prevent deficiency. Many cats thrive on more, and many commercial foods contain far above the minimum. See cat food aafco statement explained.

Comparing foods

Label percentages are affected by moisture. To compare a canned and a dry food, convert to dry-matter basis, as in how to choose wet cat food. A typical dry food may contain 30 to 40 percent protein as fed, and a wet food 8 to 12 percent as fed, which is about 35 to 55 percent on a dry-matter basis.

Protein quality

Quality depends on digestibility and amino acid balance. Animal proteins such as chicken, turkey, fish, beef, eggs and organs are highly digestible and complete. Plant proteins such as corn gluten, soy and pea are less complete, though they can be used in small amounts to add protein in foods. Look for a named animal protein among the first ingredients. See by-products and meals in cat food.

Seniors

Older cats often lose muscle, and need good protein to hold onto it. Many senior cats benefit from higher, rather than lower, protein, as long as their kidneys are healthy. Reduced digestive efficiency means they may need more. See best food for senior cats and cat weight loss causes.

Kidney disease

Cats with chronic kidney disease are often given diets with controlled phosphorus, and moderate, high-quality protein. Research shows that phosphorus restriction is the most important element. In early stages, protein restriction is not always advised, and in advanced stages, vets balance protein against appetite and muscle. Never restrict protein without your vet's advice. See cat kidney disease stages.

Other conditions

• Diabetes: high-protein, low-carbohydrate diets are often helpful. See diabetic cats: insulin, home monitoring and diet.
• Liver disease: needs tailored amounts. See hepatic lipidosis in cats.
• Overweight cats: higher protein helps preserve muscle during weight loss. See how to help an overweight cat lose weight.
• Pregnancy and nursing: need more.

Signs of too little protein

Poor coat, muscle loss, weakness, slow growth in kittens, poor wound healing and low energy. Deficiency of specific amino acids can cause heart and eye problems.

Is too much a problem?

For healthy cats, no. Excess protein is used for energy, or converted to fat, so overfeeding calories is the greater risk.

Practical tips

If your cat is healthy, a complete and balanced commercial food with a named animal protein will usually meet its needs without any calculation. Check the adequacy statement, choose the right life stage and measure portions. Weigh your cat every month or two, and watch muscle along the spine and hips, which feels bony when protein or calories are too low. If you are thinking of changing protein levels because of a health problem, bring the food label to your vet, who can calculate what suits your cat's condition and bloodwork.

When to see a vet

See a vet before changing protein levels in a cat with kidney or liver disease. Use the US vet directory to find a clinic.

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.