A cat licking his mouth after eating kibble

Why cats need (or don’t need) carbohydrates

Like all animals, cats get their energy from eating food. Food is roughly made up from three types of nutrients: protein, fats and carbohydrates. While carbs are a very essential part of most animals’ diets, cats are different because their primary source of energy is actually protein.

But while carbohydrates are not essential nutrients for cats, they can be metabolised and do provide plenty of energy.

Commercially produced cat food has a reputation for being too high in carbohydrates. And while this assumption is mostly wrong, many have adopted the belief that these foods are also responsible for the growing percentage of overweight cats.

So what’s going on, are carbohydrates in cat food the real bad guys that are responsible for our cats becoming obese, or might there be a different explanation?

First, let’s examine carbohydrates and their role in the animal body. Then we will discuss their firm presence in commercial cat foods sold in stores.

What are carbohydrates?

Animals need to eat food because it supplies the energy used by muscles during daily activities. The food contains four main components or building blocks: water, protein, fats and carbohydrates.

In cat food, carbs mostly come from grains. Examples of commonly used grains include barley, corn, oats, wheat, rye and rice. Other common sources rich in carbohydrates include pulse potatoes, beans, peas and sweet potatoes.

We can divide carbohydrates into four main types:

The four types

The classification of carbs as presented in literature from NCBI

All carbohydrates are made up from three simple atoms (carbon, hydrogen and oxygen) and can be separated into two main groups:

  • Digestible carbs

These are the simple sugars such as glucose & fructose. They are also known as absorbable carbs because they can easily be absorbed into the cells, where they will provide a quick burst of energy to the body.

  • Indigestible carbs

These are the larger sugars which are classified into polysaccharides and oligosaccharides. The polysaccharides (also known as complex carbs) are further seperated into animal and plant based large sugars. As you can see in the figure, they are at the basis of some very essential processes in the body.

Note: we have chosen to ommit the terms fermentable & non-fermentable carbs because they are not essential to this article.

Why animals need carbs

While proteins and fats can supply the body with energy, their digestion is far from efficient. Carbs, on the other hand, are super easy to burn and provide a lot of energy at little cost or investment from the body. As an additional benefit, heat is also produced during the breaking down of carbs. which helps to keep the body warm. Carbs also provide the building blocks for other key nutrients, such as vitamin C and several nonessential amino acids.

Excess carbohydrates can be converted into fats to be stored by the body for use in the future. The more unused carbs are ingested, the faster fat tissue will build up in numerous areas of the body.

Carbs in cat food

As we have seen in the previous section, carbohydrates come in various types. Some of them are more essential than others.

The indigestible carbs are very much necessary to support the body. They have a key role in all the different processes going on inside. Fiber helps with digestion, starch provides a large supply of energy, and glycogen is the main fuel stored in muscles.

The digestible carbs however, are the simple sugar units that are not necessary to body function. The problem is that many cheap cat foods contain a lot of the digestible carbs. When cats eat a lot of these, they are converted into fat.

The effect of excessive carbohydrate intake on feline health

One of the biggest concerns is the poor abilty of cats to digest carbs. There is a relationship between high carbohydrate diets and the rise of long-term metabolic diseases like obesity and feline diabetes.

Low-carbohydrate diets, on the other hand, have been suspected to help in the prevention and treatment of such illnesses.

So what is the best diet for cats?

Nutritional experts agree that cats do best on a diet that is relatively low on carbohydrates, and it MUST contain a lot of animal-sourced protein. Be aware that the nutritional needs of cats change as they grow older: a young kitten is growing fast, which means her body needs a lot more protein compared to an older senior.

Final thoughts

Grains and other sources of carbohydrates should only play a minor role in a cat’s diet. Too many grains in a cat’s diet can lead to malnutrition, obesity, organ issues, and GI tract issues. (Source)


Cats and carbohydratea: fueling your feline – Diamondpet

Cats and Carbohydrates: The Carnivore Fantasy? –Adronie Verbrugghe & Myriam Hesta

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