On a bag of kibble, you usually find protein, fat, fiber, and ash. But what about carbohydrates? Their percentage is often missing.
And between "grain-free," starch, and carbohydrate calculation, it quickly becomes difficult to know what you are actually comparing.
In our article How to read the composition of your dog's kibble?, we presented an initial calculation method. Let's now take the time to understand what it indicates… and what it does not say.
🌾 What are carbohydrates?
Carbohydrates encompass several families of substances found particularly in plants. The word does not, therefore, refer only to sugar with a sweet taste.
To read a composition, three markers are useful:
- Sugars: simple carbohydrates, generally present in small quantities in kibble.
- Starch: long chains of glucose that serve as an energy reserve for plants.
- Dietary fiber: mainly carbohydrates that a dog's digestive enzymes do not break down like starch.
👉 Carbohydrates, starch, and fiber are therefore not three interchangeable words.
What are they used for in dogs?
Properly prepared starch can be digested and provide energy. Dogs have digestive enzymes capable of breaking it down.
Fiber plays other roles: depending on its nature and quantity, it can contribute to transit, stool consistency, and satiety. Some are fermented by the intestinal microbiota, i.e., the microorganisms present in the gut.
Tolerance, however, depends on the food and the dog. The presence of starch is not enough to make a recipe unsuitable, and more fiber is not necessarily better.
🏷️ Why is the carbohydrate rate not indicated on the bag?
In the European Union, the labeling of compound feed for dogs provides, among other things, for the declaration of crude protein, crude fat, crude fiber, and crude ash. The total carbohydrate rate is generally not part of the mandatory analytical constituents.
Moisture is also not always displayed on dry food: for ordinary kibble, its declaration becomes mandatory when it exceeds 14%.
The absence of a "carbohydrates" line is therefore not, by itself, proof of a desire to hide the composition. To obtain more details, you can ask the manufacturer for their full nutritional analysis.
🧮 How to estimate carbohydrates with NFE?
We commonly use the Nitrogen-Free Extract, or NFE. This somewhat technical name refers to what remains when the other measured fractions are subtracted from 100%.
NFE (%) = 100 − protein − fat − fiber − ash − moisture
Use the values of the analytical constituents, all expressed as a percentage of the food as sold. Here, "fiber" means crude fiber or "crude cellulose" on some labels, and "ash" means crude ash. Do not use ingredient percentages in their place.
A simple example
Let's use the values from our article on reading kibble:
- protein: 30%;
- fat: 16%;
- crude fiber: 3%;
- crude ash: 8%;
- moisture: 9%.
100 − 30 − 16 − 3 − 8 − 9 = 34% NFE.
This represents approximately 34 g of NFE per 100 g of kibble as sold. It is neither 34% grains, nor an exact measurement of starch, nor 34% of the food's calories.
And if moisture is missing?
The best reflex is to ask the manufacturer for it, along with ash if it is also missing. An absent value does not equal zero.
You can perform a provisional calculation with an assumption, but it must be clearly stated. In our example, an assumed moisture of 8% would give 35% NFE; with 10%, you would get 33%.
👉 A two-point difference can thus come simply from the water retained in the calculation. Avoid choosing between two recipes based on a small gap when the data is incomplete.
🔎 Limitations: an estimate, not a starch analysis
NFE mainly groups starch and sugars, but also a portion of the fiber not accounted for by the crude fiber analysis. It can therefore overestimate the truly digestible carbohydrates.
Label rounding, manufacturing variations, and the uncertainties of each analysis also affect the result.
This calculation does not allow you to know:
- the exact quantity of starch and sugars separately;
- the total dietary fiber;
- the digestibility of the starch or the quality of its cooking;
- the dog's glycemic response, i.e., the evolution of its blood glucose after the meal.
To go further, ask for a starch dosage, and if possible, sugars and total dietary fiber. Also check if the figures are expressed on the food as sold or on dry matter.
⚙️ Why is there starch in extruded kibble?
Extrusion combines water, heat, pressure, and mechanical work, among other things, to transform the mixture of ingredients.
During this process, the starch gelatinizes: its structure transforms, which contributes to the cohesion, expansion, and texture of the kibble. This preparation also makes it easier for digestive enzymes to access it.
It therefore has a technological and energy role. The quantity used depends on the recipe and the process; one cannot deduce a universal nutritional threshold from this manufacturing need.
🌱 Grains and other starch sources: what are we comparing?
An ingredient does not provide just one nutrient. Its form matters as much as its name: whole grain, flour, isolated starch, proteins, or fiber do not correspond to the same raw material.
Rice, corn, wheat, oats
These grains can all provide starch, with varying proportions of protein, fiber, and fat.
- White rice is generally lower in fiber than brown rice.
- Corn and wheat provide starch and protein; corn starch does not have the same profile as a whole grain of corn.
- Oats notably provide fiber, including beta-glucans, in quantities that vary according to their processing.
Peas and lentils
These legumes provide starch, but also plant proteins and fiber. Their presence can therefore influence several lines of the analytical constituents.
"Peas," "pea protein," and "pea starch" are not equivalent. Read the whole list, without considering each form as a purely carbohydrate ingredient.
Potato, sweet potato, and tapioca
Potato and sweet potato also provide starch. Their profile varies depending on whether they are used whole, dehydrated, or in the form of starch.
Tapioca, derived from cassava, is mainly a source of starch and provides little protein and fiber in its refined form.
None of these families is automatically superior to the others. The quantity incorporated, the treatment, the balance of the recipe, and individual tolerance matter more than a general ranking of ingredients.
🌾 "Grain-free" does not mean "carbohydrate-free"
Kibble without rice, corn, or wheat may contain peas, lentils, potato, sweet potato, or tapioca.
The grains have then been replaced by other ingredients which can also provide a lot of starch.
A "grain-free" recipe can therefore have an NFE comparable to, lower than, or higher than that of a recipe with grains. The mention does not allow you to predict the result of the calculation.
It also does not guarantee better digestibility for your dog.
🐾 A percentage is not enough to judge a kibble
Two foods with the same NFE can have different sources of starch, fiber, digestibility, and energy density.
Conversely, a lower NFE can be accompanied by more fat or protein. This does not automatically make the food more suitable, especially if the ration provides too many calories.
As we explain in Protein in the dog's diet, the quantity of a nutrient must be linked to its quality and the overall balance of the food.
Therefore, also check whether the kibble is a complete food adapted to the dog's age and needs, then take into account its activity, body condition, the distributed ration, and its digestive tolerance. In the event of illness or persistent disorders, the choice should be made with your veterinarian.
🐺 The Sköll & Hati perspective
To compare the carbohydrate fraction of two kibbles, I follow five steps:
1. I gather the same data for both foods.
Protein, fat, crude fiber, ash, and moisture. I note the missing values and assumptions, without turning them into certainties.
2. I calculate the NFE for each recipe.
For our kibble A: 100 − 30 − 16 − 3 − 8 − 9 = 34%.
For a fictional kibble B: 100 − 32 − 18 − 4 − 8 − 10 = 28%.
3. I compare on the same basis.
To remove the effect of water: NFE on dry matter = NFE ÷ (100 − moisture) × 100.
A: 34 ÷ 91 × 100 ≈ 37.4%.
B: 28 ÷ 90 × 100 ≈ 31.1%.
B presents a lower estimated NFE here, even after correcting for moisture. This describes a difference in composition, not a quality verdict. These values remain estimates and do not represent a share of the calories.
4. I look at what is behind the result.
What starch sources? In what forms? How much crude fiber? Does the manufacturer provide the measured starch, total fiber, or digestibility data? I do not compare a starch dosage to an NFE as if it were the same figure.
5. I return to my dog.
I compare this information with the protein, lipids, calories per ration, and its needs. Then I observe its weight, body condition, and stools after a gradual dietary transition. A lower NFE is not a sufficient reason to change a food that suits them.
Documentary references: FEDIAF scientific review on carbohydrates, FEDIAF fact sheet on grain-free food and European regulation on pet food labeling. FEDIAF represents the European pet food manufacturers.
Key takeaways
- Grain-free does not mean carbohydrate-free.
- NFE is calculated by difference: it is an estimate, not a starch dosage.
- Compare complete data, on the same basis, then look at the ingredients and the balance of the recipe.
- The right choice depends on your dog's needs and tolerance, not on an isolated percentage.