When looking at a bag of cat kibble, you can easily find the levels of protein, fat, fiber, or even minerals. Yet, one piece of data is attracting more and more attention from owners: carbohydrates.
And paradoxically, their amount is generally not indicated directly on the label.
This sometimes leads to two opposing shortcuts: considering that all carbohydrates are bad for cats, or conversely, that they are of no importance since they do not appear clearly in the analytical constituents.
The reality is more nuanced. Cats can use dietary carbohydrates, but their presence, and especially their proportion, must be put into the context of the overall formulation.
Why are there carbohydrates in kibble?
Carbohydrates include various molecules, including sugars, starch, and certain dietary fibers.
In kibble, starch has an important functional role. It contributes to the manufacture and structure of the kibble during the extrusion process.
It can come from various raw materials:
- rice;
- corn;
- wheat;
- potatoes;
- peas;
- lentils;
- sweet potatoes;
- tapioca.
This is why a grain-free kibble is not a carbohydrate-free kibble. The grains are simply replaced by other sources that can provide starch.
Cats are obligate carnivores
Cats have nutritional needs characteristic of an obligate carnivore.
Proteins play an essential role in their metabolism, and certain indispensable nutrients must be provided by their diet.
However, this does not mean that their body is incapable of using any carbohydrates at all.
Properly processed and cooked starch can be digested by cats. Claiming that "cats cannot digest carbohydrates" would therefore be inaccurate.
The real question is not whether there should be zero carbohydrates, but rather understanding what role carbohydrates play in the ration compared to the other nutrients the cat needs.
Why does their amount not appear on the bag?
On pet food, the analytical constituents generally indicate:
- crude protein;
- crude fat;
- crude fiber or cellulose;
- minerals or crude ash;
- sometimes moisture.
Digestible carbohydrates do not generally appear as a "carbohydrates: X%" line.
However, one can obtain an estimate by difference when all the necessary data is available.
The commonly used calculation is:
100 − protein − fat − fiber − minerals − moisture = estimated nitrogen-free extract
This value provides an approximation of the fraction mainly composed of digestible carbohydrates.
It must be emphasized that this is an estimate: this calculation does not replace a laboratory analysis and depends on the information provided on the label.
Beware of moisture in the calculation
This is a detail that can significantly change the result.
When the manufacturer does not indicate the moisture content of the kibble, a piece of data is missing to correctly perform the calculation on the product as is.
One should therefore not invent a value and then present the result as an exact rate.
To seriously compare several foods, it can also be useful to reason based on dry matter, that is to say by removing the effect of water.
This precaution becomes particularly important when comparing kibble and wet food: their water contents are so different that comparing their percentages directly can be misleading.
Does a high carbohydrate rate mean the kibble is bad?
Not automatically.
A food cannot be properly evaluated based on a single figure.
One must also look at its protein content, the origin of that protein, fats, energy density, fibers, minerals, general nutritional balance, and the cat's needs.
However, when a large part of the recipe is based on starch sources, it is legitimate to ask what is left for ingredients that provide nutrients particularly important for an obligate carnivore.
Monitoring carbohydrates therefore mainly allows for a step back to look at the overall formulation.
Conversely, does less carbohydrate necessarily mean better?
Not necessarily.
A kibble showing a relatively low estimate of carbohydrates is not automatically excellent.
The decrease in one nutrient implies that the proportion of others increases. You therefore need to know what the carbohydrates have been replaced with.
A formula might be richer in protein or fat, for example. This changes its nutritional profile and potentially its energy density.
The lowest figure is therefore not necessarily the best for all cats.
The goal remains to choose a diet that is consistent as a whole.
The "grain-free" trap
Confusion between grains and carbohydrates is particularly common.
A grain-free food can use peas, potatoes, tapioca, or other starch sources in their place.
It is therefore perfectly possible for a grain-free recipe to contain as many, or even more, estimated carbohydrates than a recipe containing rice or corn.
This is why the "grain-free" logo placed on the front of the bag is not enough to compare two kibbles.
It answers the question:
Are there grains in this recipe?
It does not answer:
What amount of carbohydrates does it contain?
These are two different questions.
Not all carbohydrates are the same
The word "carbohydrates" covers several categories.
Starch does not have the same role as dietary fiber, for example. Fibers are, moreover, generally considered separately in nutritional analyses and can have different effects on transit, satiety, or the intestinal microbiota depending on their nature.
It is therefore necessary to avoid lumping "carbohydrates," "sugars," "grains," and "fibers" into the same basket.
Saying that a kibble contains carbohydrates does not mean it is filled with table sugar.
This distinction is important when trying to truly understand a label rather than stopping at a frightening term.
Carbohydrates and weight gain: beware of the shortcut
Carbohydrates are sometimes singled out as the sole culprits for excess weight in cats.
Once again, it is too simple.
Weight gain occurs when energy intake consistently exceeds the animal's expenditure. Fats are also very energy-dense, and the total amount of calories consumed remains the determining factor.
A cat can therefore gain weight on various dietary profiles if its ration provides more energy than it spends.
For a neutered or sedentary cat, or one with a tendency to put on weight, you must look at the energy density of the food and, above all, adapt the amounts provided.
Monitoring carbohydrates can be part of the analysis, but it is not the only criterion.
And for a diabetic cat?
In the context of diabetes, the composition of the diet can have particular importance.
But a diabetic cat should not simply be switched to the kibble showing the lowest carbohydrates after a calculation performed at home.
The choice of diet is part of their medical management and must be adapted with the veterinarian, particularly because dietary changes can influence treatment requirements.
The question of carbohydrates then becomes a medical and individual one, rather than simply a criterion for comparing two bags in a store.
How to intelligently compare two kibbles?
Rather than looking for a magic number, you can proceed in steps.
Start by reading the list of ingredients and identifying the main raw materials. Then look at the analytical constituents: protein, fat, fiber, minerals, and moisture when indicated.
If the data allows, then estimate the carbohydrate fraction.
Then put this result into the context of the recipe as a whole.
A kibble should not be chosen just because it displays:
"40% protein",
"grain-free",
or "only X% carbohydrates".
This is interesting information, but none of it describes the overall quality of the food on its own.
Key takeaways
Carbohydrates are neither a poison that must absolutely be eliminated nor an element that should be ignored under the pretext that the cat can digest them.
Monitoring them primarily allows for a better understanding of how a kibble is formulated.
The cat remains an obligate carnivore with specific nutritional needs. The role of protein and fat, the origin of ingredients, the energy intake, and the general balance of the ration must therefore be studied alongside the carbohydrate fraction.
And above all:
grain-free does not mean carbohydrate-free,
a low carbohydrate rate does not by itself guarantee good kibble,
and a high rate does not allow for judging a food without examining the rest of its composition.
At Sköll & Hati, the goal is not to look for a perfect number on every bag, but to understand what the numbers say together.