How to Read a Cat Food Label: Guaranteed Analysis Explained

Every bag of cat food sold in the US carries a small box called the guaranteed analysis. It lists at least four numbers: crude protein, crude fat, crude fiber and moisture. Some makers add ash, taurine or other nutrients. Together with the calorie statement, it is where the maker commits to numbers, and it is what our Nutrition score is built from.

What the Guaranteed Analysis Guarantees

The numbers are limits, not exact amounts. Protein and fat are minimums: a bag that says "crude protein (min) 36%" contains at least 36%. Fiber and moisture are maximums. Two foods that both say 36% protein can differ a little in the bag, and the label will not tell you which one is higher.

The numbers are also "as fed": they describe the food as it comes out of the bag or can, water included. That is fine when you compare two dry foods; on our list moisture runs from 7.5% to 12%. It is misleading when you put a dry food next to a wet one, because a can is mostly water. A can that says 10% protein is not a low-protein food. The next section shows why.

"Crude" refers to the lab method, not to quality. Protein is worked out from the nitrogen in the food; fat and fiber are measured by extraction. It is a standard measurement, not a count of what a cat can digest.

Dry Matter: The Fair Comparison

To compare foods with different moisture, take the water out on paper. Divide each nutrient by the dry share of the food, which is 100 minus moisture, and multiply by 100. Orijen Original Cat has 10% moisture, so its dry share is 90%, and its 40% protein becomes 44.4% on a dry matter basis.

Here is the same arithmetic next to a typical canned pate. The canned figures are an example, not a specific product.

On the label the can looks like a quarter of the kibble's protein. With the water removed, the two are almost the same. Every food page on Pettings shows the label value and the dry matter value side by side.

One thing to know about our own scores: the Nutrition score uses the label values, not dry matter. For dry foods the difference is small, because moisture on our list stays between 7.5% and 12%. Wet foods are not on Pettings yet.

Carbohydrates: The Number That Is Usually Missing

Most US labels do not list carbohydrates. You can work them out: whatever in the food is not protein, fat, fiber, ash or water is carbohydrate. So carbohydrate is roughly 100 minus protein, fat, fiber, ash and moisture.

Ash is the mineral content left when food is burned in a lab. It is not required on US labels either; when a bag leaves it out we assume 7%, a typical value for dry cat food, and say so on the food's page.

Take Taste of the Wild Lowland Creek: protein 36%, fat 16%, fiber 3%, moisture 10%, ash not listed. 100 minus 36, 16, 3, 7 and 10 leaves 28% carbohydrate as fed, or about 31% on a dry matter basis. That is a grain-free food, which shows how little the front of the bag tells you about starch.

Some bags already use a newer label format that lists total carbohydrates. That figure includes dietary fiber, so we subtract the fiber to keep those foods comparable with the rest. Purina ONE Tender Selects lists 38% total carbohydrates and 10% dietary fiber, so we count 28%. Because the label numbers are minimums and maximums, every carbohydrate figure is an estimate, and we present it as one.

What Counts as a Good Number

AAFCO's Cat Food Nutrient Profiles set the minimums a food labeled complete and balanced has to meet, measured on a dry matter basis. Our target ranges sit above them. They are not rules, only where a food gets full points from us, and they are label values, not dry matter.

Kitten and weight control foods have their own ranges on the How We Score page. A value inside the range gets full points and loses them step by step the further it drifts, on either side. Protein counts three times in the score, fat twice, carbohydrates once.

Most dry foods clear the protein minimum by a wide margin. Corn gluten meal and pea protein raise the protein percentage without adding meat, and the guaranteed analysis cannot tell you that. The ingredient list can.

The Rest of the Label in One Minute

The adequacy statement is the sentence that says whether the food is a meal. Look for "complete and balanced" for a named life stage, backed either by AAFCO nutrient profiles or by a feeding trial. "For intermittent or supplemental feeding only" means it is a treat or a topper, whatever the front of the bag suggests.

The calorie statement gives kcal per kilogram and usually per cup. On our list it runs from 3,195 to 4,532 kcal/kg, so two foods with similar protein can feed very differently. The denser one feeds a cat on a smaller portion, which changes the real monthly cost. Every food page on Pettings turns the feeding chart, or the calories when there is no chart, into a monthly estimate by cat weight.

Ingredients are listed in descending order by weight, so the first few weigh the most. Check whether they are named animals (chicken, salmon meal) or groups (poultry, meat, fish meal), and whether a plant protein sits among them. The guaranteed analysis tells you how much protein; the ingredient list tells you where it came from. You need both.

If your cat has a health problem, these numbers are a starting point for a conversation with your vet, not a substitute for one.

Related: Is Grain-Free Cat Food Bad for Cats?

Sources

• AAFCO, "Reading Labels": guaranteed analysis, the meaning of "crude", ingredient order, calorie statement.
• AAFCO Cat Food Nutrient Profiles (protein, fat and taurine minimums, dry matter basis), AAFCO Official Publication.
• Pettings, How We Score: target ranges, carbohydrate estimate, ash assumption.
• Pettings, Cat Food Questions.
• Food figures from the Pettings pages linked above, copied from the makers' labels.

Scores describe what the label says. They are not medical advice.