Slices of seeded low-carb bread and folded low-carb wraps on a wooden board beside blank kraft-paper food packets and a brass magnifying glass

Do You Subtract Fibre From Carbs on UK Labels? Net Carbs Explained

October 16, 2026

Quick answer: No, you don't subtract fibre from carbs on a UK food label. UK nutrition labels list fibre separately from carbohydrate, so the carbohydrate figure already excludes fibre and works like a "net carbs" number. The advice to subtract fibre comes from American labels, where fibre is included in Total Carbohydrate. The one grey area in the UK is polyols, such as erythritol, which are counted inside the carbohydrate figure.

If you've learned keto from American YouTube channels, recipe sites or tracking apps, you've probably been told to "take the fibre off the carbs". On a UK pack, that step has already been done for you. Do it again and you'll undercount, sometimes to the point of getting a negative number. This guide explains why, shows how UK and US labels differ, and gives you a simple way to count carbs from any British label.

Why UK carbohydrate already excludes fibre

Food labels in Great Britain follow the assimilated Food Information to Consumers Regulation (Regulation (EU) No 1169/2011, kept in UK law after Brexit). It defines the terms used in the nutrition table:

Carbohydrate means "any carbohydrate which is metabolised by humans, and includes polyols".
Fibre means carbohydrate polymers that are "neither digested nor absorbed in the human small intestine".

Because fibre isn't metabolised in the same way, it isn't part of the carbohydrate figure. It gets its own line further down the table, after carbohydrate and before protein. Fibre is also optional on UK labels, so some packs don't show it at all. That doesn't change anything: the carbohydrate figure still excludes it.

A typical UK nutrition table runs in this order: energy, fat, of which saturates, carbohydrate, of which sugars, fibre, protein and salt. Note that sugars sit inside carbohydrate ("of which sugars"), but fibre doesn't.

UK vs US labels: the key difference

	UK label	US label
Main carb line	Carbohydrate	Total Carbohydrate
Is fibre included?	No, fibre is listed separately	Yes, Dietary Fiber sits inside the total
Are polyols included?	Yes	Yes (shown as sugar alcohols, if listed)
To get "net carbs"	Use the carbohydrate figure, then decide about polyols	Subtract fibre (and often sugar alcohols) from the total

Here's how that plays out. Imagine an American snack bar labelled with 12g Total Carbohydrate and 8g Dietary Fiber. An American keto follower would subtract the fibre and count 4g net carbs. Sold in the UK, the same bar would show roughly 4g carbohydrate, with 8g fibre listed separately. Both routes land on about the same number, but only one of them involves subtracting anything.

Imported products are where people get caught out. If you buy an American product in the UK, check whether it has a "Nutrition Facts" panel with "Total Carbohydrate", or a UK-style table, sometimes on an importer's sticker. Only the US version needs fibre taken off.

The double-subtraction mistake (with real examples)

The quickest way to see the problem is to apply US maths to a UK label.

When fibre is higher than carbs

Our Low Carb Keto Wraps list 4.4g carbs and 10.4g fibre per wrap. Subtract the fibre from the carbs and you'd get minus 6g, which is impossible. The 4.4g figure is the one to count, and the fibre has already been taken out of it.

When the numbers are close

Our Low Carb Keto Bread shows 2.3g net carbs and 2.2g fibre per slice. Subtract one from the other and a slice looks like it has almost no carbs at all. In reality, 2.3g per slice is what you log. Over a day of toast, sandwiches and wraps, double-subtracting like this can hide a surprising amount of carbohydrate from your tracker.

If you're weighing up which breads and wraps fit a low-carb day, our guide Can You Eat Wraps on Keto? compares the options in more detail.

Where polyols fit in

Polyols, sometimes called sugar alcohols, are the one part of a UK carbohydrate figure that keto followers often treat differently. Common examples are erythritol, xylitol, maltitol and sorbitol. Under UK law they count as carbohydrate, and a label may show them as a sub-line: "of which polyols". Showing polyols is voluntary, so not every pack will.

The labelling rules themselves treat polyols differently from each other. For calculating the energy on a label, most polyols are counted at 2.4 kcal per gram, but erythritol is counted at 0 kcal per gram. That's one reason many keto followers subtract erythritol from their personal carb count but still count maltitol and other polyols, at least in part.

This matters if you bake with an erythritol-based sweetener such as our Monk Fruit Decoction & Erythritol Sweetener, which measures 1:1 like sugar. Under UK rules, the erythritol in it is counted within carbohydrate on the label, so check for an "of which polyols" line when you're working out your own numbers. For more on how erythritol compares with monk fruit, read Monk Fruit vs Erythritol: Key Differences.

How to count carbs from a UK label: step by step

Find the carbohydrate line. Use "Carbohydrate", not "of which sugars". Sugars are only part of the total.
Leave fibre alone. It's already been excluded, however large the number is.
Scale to your portion. Most UK figures are per 100g. Multiply by the weight you'll actually eat and divide by 100. For example, a food with 8g carbohydrate per 100g gives 2.4g in a 30g portion (8 × 30 ÷ 100).
Check for polyols. If there's an "of which polyols" line, decide how you want to treat it. Erythritol is the one most keto followers leave out.
Check where the product is from. If it carries a US "Nutrition Facts" panel, that's the only time you subtract fibre.

Tracking apps and UK foods

Many popular carb-tracking apps were built around US label data, and some calculate net carbs automatically by subtracting fibre from whatever you enter as total carbohydrate. If you type in a UK carbohydrate figure and the fibre, the app will remove the fibre a second time.

There are two easy fixes. Either enter the fibre as zero when you add a UK food, or enter "total carbs" as the UK carbohydrate figure plus the fibre, so the app's subtraction brings you back to the right number. It's also worth spot-checking barcode scans against the pack, as crowd-sourced entries sometimes mix up UK and US figures.

Is "net carbs" an official UK term?

No. "Net carbs" isn't defined anywhere in UK nutrition labelling law, and it can't appear inside the nutrition table, because that table may only list the nutrients set out in the regulations. When a brand mentions net carbs, it's describing its own figures elsewhere on the pack or online. On a UK label, that number should usually match the carbohydrate line, unless polyols have been treated differently. If they have, a good brand will tell you how it was worked out.

If you're managing diabetes or any other medical condition, speak to your GP, diabetes team or a registered dietitian before relying on net carb figures, particularly for medication or insulin decisions.

Frequently asked questions

Do you subtract fibre from carbs on UK food labels?

No. On a UK label, fibre is listed separately and is not included in the carbohydrate figure, so the carbohydrate line already works like a net carb figure. Subtracting fibre again would undercount your carbs.

Are UK carbs the same as net carbs?

Broadly, yes. UK carbohydrate excludes fibre, which is what most people mean by net carbs. The main exception is polyols such as erythritol, which UK law counts as carbohydrate, so some keto followers subtract erythritol for their own tally.

Why do American keto recipes tell you to subtract fibre?

Because US Nutrition Facts labels include dietary fibre within Total Carbohydrate. Americans subtract fibre to reach net carbs. UK labels have already separated it out, so the same advice does not apply.

Can a UK product have more fibre than carbohydrate?

Yes. The two are separate figures, so fibre can be higher than carbohydrate. Groovy Keto Low Carb Keto Wraps, for example, list 4.4g carbs and 10.4g fibre per wrap. It does not mean the food has negative carbs.

Should I subtract erythritol on a UK label?

That is a personal choice. Erythritol is a polyol, so it sits inside the UK carbohydrate figure, but it is the only polyol given an energy value of zero in UK labelling rules. Many keto followers leave it out of their count, while counting other polyols such as maltitol.

Can a UK brand print net carbs in the nutrition table?

No. The nutrition declaration may only list the nutrients set out in UK law, and net carbs is not one of them. Brands that use the term have to show it elsewhere on the pack or online.