Working out the carbohydrate in UK cat food, with worked examples

Quick answer

Take the figures off the label, work out carbohydrate as fed, then convert it to a dry matter basis. Both steps, every time.

Step 1   carbohydrate as fed = 100 − (protein + fat + ash + fibre + moisture)
Step 2   dry matter carbohydrate = carbohydrate as fed ÷ (100 − moisture) × 100

Skipping step 2 makes wet food look dramatically lower in carbohydrate than it is, because most of a tin is water. Aim for 5–10% on a dry matter basis.

Why we have not published a brand list

It would be the most useful thing on this page and we are not going to do it, for two reasons.

Recipes change without the name changing. A figure we calculate today can be wrong within a year, on a page that looks authoritative and dated. Published brand tables go stale quietly, and an owner trusting one is worse off than an owner doing the sum.

Our figures would not be measurements. They would be arithmetic on a label, with the same limitations as yours — including the ash problem below. Presenting that as a verified list would be implying a rigour we do not have.

So this page teaches the method instead, with worked examples you can check. Do it once in the shop and it takes a minute; the skill does not go out of date.

Worked example: a typical pâté

A tin shows: protein 10%, fat 6%, ash 2%, fibre 1%, moisture 78%.

Step 1   100 − (10 + 6 + 2 + 1 + 78) = 3% carbohydrate as fed
Step 2   3 ÷ (100 − 78) × 100 = 13.6% on a dry matter basis

3% looks excellent. 13.6% is above the 5–10% you are aiming for and more than halfway to the 25% consensus ceiling. An owner comparing the as-fed figure against a dry-matter target would buy this believing it was well inside range.

Worked example: food in gravy

A pouch shows: protein 8%, fat 4%, ash 2%, fibre 0.5%, moisture 82%.

Step 1   100 − (8 + 4 + 2 + 0.5 + 82) = 3.5% carbohydrate as fed
Step 2   3.5 ÷ (100 − 82) × 100 = 19.4% on a dry matter basis

Nearly twice the previous example despite a near-identical as-fed figure, because there is less dry matter to divide by. This is the general pattern: gravy and jelly carry starch, and the thinner the food the more the conversion bites.

Worked example: dry food

A dry food shows: protein 34%, fat 14%, ash 7%, fibre 3%, moisture 8%.

Step 1   100 − (34 + 14 + 7 + 3 + 8) = 34% carbohydrate as fed
Step 2   34 ÷ (100 − 8) × 100 = 37% on a dry matter basis

Here the two figures are close, because there is little water to remove. It also shows why dry food is hard to get low in carbohydrate: starch is what holds a kibble together.

The ash problem

Plenty of UK labels give a "typical analysis" without ash, which leaves a hole in step 1. Treating the missing value as zero inflates your carbohydrate figure; guessing 2–3% for wet food is common practice but it is a guess.

If ash is missing, treat your answer as approximate and ask the manufacturer for a full typical analysis. Most will send one, and a brand that will not is telling you something.

What to do with the answer

Take it to your vet rather than acting on it alone. A diet change alters how much insulin a cat needs, so it is a conversation to have before you switch, not after — and a cat with kidney disease, pancreatitis or a food aversion may need something else entirely.

The companion guide to feeding a diabetic cat covers portions, meal timing around insulin and how to transition without the cat refusing food.

Sources and further reading

• 2025 iCatCare consensus guidelines on the management of diabetes mellitus in cats.
• AAHA Diabetes Management Guidelines for Dogs and Cats.

General information about reading labels, not advice about an individual animal. Your vet chooses the diet for your cat.