Choosing a food suitable for your cat can be confusing. The choice is seemingly endless, with hundreds of different types, brands, textures and flavours available. Cats are carnivores, and so protein is an important part of your pet’s nutrition. But how do you know how much protein is good? Are high protein diets good? Or low protein? What even is protein anyway?!

Read on to find out what protein is, why cats need it and how much they actually should be getting!

What is protein?

Proteins are large molecules made up of chains of smaller amino acids. They are necessary for most biological processes in the body, especially growth and repair. Thousands of different proteins are found throughout the body, in muscle, bone, hair, skin and organs. 

Why do cats need protein?

Cats are obligate carnivores – they rely on animal protein as their main diet. They are physiologically designed to mostly eat meat, and therefore have quite specific dietary needs. A cat’s natural diet would consist of animal prey such as birds and small mammals. 

Cats are well adapted to diets that are low in carbohydrate, and high in protein, and rely much more on protein as an energy source than carbohydrate. Cats also require meat to provide certain vitamins and nutrients such as essential fatty acids.  

Our feline friends are unable to make certain nutrients themselves, and therefore rely on dietary intake. The amino acids taurine, arginine, methionine and cysteine are essential for health; and cats rely upon dietary protein sources for these. Taurine is found only in animal protein, not in plants. Methionine and cysteine are found in plants, but in only very small amounts. And cats need them in large quantities, especially growing kittens. Some plants contain arginine, but not all, and without it, a cat’s liver cannot function properly. Without the correct protein levels – both source and amount – to make these amino acids, cats may become severely unwell and even die. 

Protein needs and how they differ

Feeding your cat a complete diet is important for health and wellbeing. A balanced, appropriate diet provides your kitty with the nutrients they need for activity, growth, health and development. 

However, what is a suitable diet for a kitten may not be as balanced for a senior cat, or a pregnant queen. And a normal adult diet may not suit a cat with a chronic health condition. Protein needs vary throughout life, as rates of growth and development change, and various demands are placed upon our cats’ bodies. 

Adult cats

Healthy, active adult cats should be fed a diet that is well balanced in terms of protein, carbohydrates and fats. Cats have not differed significantly in their digestive physiology from their wildcat ancestors, who would have survived on prey such as mice, which are made up of 55% protein on dry matter analysis. 

The European Pet Food Industry Federation (FEDIAF) recommend in their guidelines that adult cats should be fed a protein level of 25-33g/100g DM (dry matter), depending on their activity level and energy needs. The Association of American Feed Control Officials (AAFCO) recommend a minimum protein level of 26g/100g dry matter (30%). Most commercial cat diets have protein levels that are significantly higher than this, which is fine – there is no known risk in healthy adult cats to have dietary protein levels which exceed these minimum values.


Rapid growth requires protein, and so kittens have a generally higher protein requirement than adult cats. Kitten food will generally have higher protein and calorie levels than a maintenance cat food, to support growth and development. FEDIAF recommend a minimum protein level of 28g/100g DM, and AAFCO recommend a minimum of 30%. 

Senior cats

Older cats require a diet high in digestibility, as they become less able to efficiently break down nutrients. Protein levels are important to maintain their lean body mass, with older cats being prone to lose weight and muscle. In healthy senior cats, a high protein diet (around 40%) may be beneficial to maintain body condition. However, there are some health conditions such as kidney disease that are common in older cats, and require a low protein diet, so many senior cat diets actually have lower protein levels, but higher protein quality, than adult diets.

Pregnant and nursing queens

Expectant and new mother cats will also require higher levels of protein, due to fuelling the growth and nutrition of their offspring. It is usually recommended that a kitten diet with its high protein and calorie levels would be a suitable choice for this life stage. A protein level of around 30g/100g dry matter is considered advisable. 

Medical conditions

There are some health concerns that may cause you to choose a diet with a specific protein level for your cat. Liver and kidney disease are both best managed with low protein diets. Cats struggling with chronic gastrointestinal disorders require highly digestible protein in good levels, as they are often losing protein via the intestines. If your cat needs to lose some weight, feeding a high protein diet could help to reduce body fat without losing lean body mass. 

Summing up

Protein is an essential dietary need for many creatures, but due to cats’ specific digestive physiology they require high levels of animal protein in their diets. Most adult cats should be eating a diet that contains around 30g of protein per 100g of dry matter. Kittens, pregnant and nursing queens, healthy senior cats and some specific health conditions may require even higher levels of digestible protein, whereas some chronic diseases may call for lower levels. If you are concerned about the best diet for your cat, speak to a veterinary professional for advice.

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