A Complete Guide on How to read carbs on food labels in the UK?

November 2, 2025 •

2 min read

According to the NHS, most people in the UK consume too much sugar, a type of carbohydrate. Learning how to read carbs on food labels in the UK? is an essential skill for managing your diet effectively, whether you're controlling blood sugar, managing weight, or just eating healthier.

Quick Summary

This guide explains the UK food label structure, focusing on carbohydrates. It details the mandatory back-of-pack information, the difference between total carbs, sugars, and fibre, and how to use the voluntary front-of-pack traffic light system. It also provides the correct method for calculating net carbs for a low-carb diet.

Key Points

Total vs. Sugar Carbs: On a UK label, 'Carbohydrate' lists the total, while 'of which sugars' shows the sugar component, including natural and added sugars.
Fibre is Separate: In the UK, the fibre content is listed in its own row and is not part of the main 'Carbohydrate' figure.
Calculating UK Net Carbs: For a low-carb diet, calculate net carbs by subtracting the value of 'of which polyols' from the total 'Carbohydrate'.
Traffic Light for Sugars: The front-of-pack traffic light system uses colours to rate sugar content (red for high, amber for medium, green for low) but does not display total carbohydrate levels.
Spotting Added Sugars: Check the ingredients list for keywords like sucrose, glucose syrup, or any ingredient ending in '-ose' listed high up, indicating a higher proportion of added sugar.
Comparing Products: Always use the 'per 100g' column to compare the carbohydrate content of similar products accurately, as portion sizes can be misleading.
Portion Size Awareness: Be mindful that the manufacturer's suggested portion size may differ from your own, potentially leading to higher carb intake than expected.

Demystifying the Back-of-Pack Nutrition Table

By law, all pre-packaged foods in the UK must carry a nutrition declaration, usually on the back or side of the packaging. This table shows energy and nutrient content per 100g (or 100ml) and often per portion.

The 'Carbohydrate' Row Explained

The carbohydrate section has two key values:

Carbohydrate (g): This is the total carbohydrate content and, unlike US labels, excludes fibre in the UK. It represents digestible carbs from starch and sugars.
of which sugars (g): This sub-category shows how much of the total carbohydrate is sugar, including natural and added sugars.

The Role of Fibre

Fibre is a carbohydrate that is not fully digested. In the UK, it is listed separately from the total carbohydrate figure and is beneficial for digestion and slowing glucose release. UK government guidelines recommend adults eat 30g of fibre daily.

Net Carbs: A UK Perspective

For low-carb diets, net carbs (carbs affecting blood sugar) are important. The UK calculation differs from the US because fibre is already separate. To find net carbs on a UK label, subtract any polyols (sugar alcohols) from the 'Carbohydrate' total. Fibre is not subtracted. If there are no polyols, the 'Carbohydrate' value is your net carb count.

The Front-of-Pack Traffic Light System

A voluntary traffic light system on the front of many UK products provides a quick visual guide to fat, saturated fat, sugars, and salt content, using green (low), amber (medium), and red (high) codes. This system does not show total carbohydrates. It's based on a 'per 100g' measure.

Deciphering the Ingredients List for Added Sugars

To identify added sugars, check the ingredients list, where items are ordered by weight. Look for common sugar names like sucrose, glucose syrup, fructose, and others listed near the beginning. For detailed information on food labelling, consult the Food Standards Agency.

UK vs. US Carbohydrate Labelling: A Comparison


Feature	UK Food Label	US Food Label
Total Carbohydrate	Excludes fibre.	Includes fibre.
Fibre	Listed separately.	Included in Total Carbohydrate.
Net Carbs Calculation	Subtract polyols from 'Carbohydrate'.	Subtract fibre and polyols from 'Total Carbohydrate'.
Polyalcohols (Polyols)	Listed as 'of which polyols'; subtract for net carbs.	Included in Total Carbohydrate; often subtracted for net carbs.
Overall Complexity	Simpler for net carb counting.	Requires an extra step to subtract fibre.

Conclusion

Understanding UK food labels, particularly the carbohydrate section and the distinction between total carbs, sugars, and fibre, is vital for managing your diet. The separate listing of fibre simplifies net carb calculation for low-carb diets by only requiring the subtraction of polyols. The traffic light system offers a quick reference for sugar content, and the ingredients list helps identify added sugars. Using the 'per 100g' values for comparison ensures accurate dietary tracking, allowing you to make informed choices aligned with your nutritional goals.

Frequently Asked Questions

In the UK, fibre is listed separately and is not included in the 'Carbohydrate' total. In contrast, US labels include fibre within the 'Total Carbohydrate' figure, so you must subtract it manually for net carb counting.

On a UK label, you simply need to subtract the value of 'of which polyols' (if present) from the main 'Carbohydrate' figure. You do not need to subtract fibre, as it is already separate.

The 'of which sugars' line specifies how much of the total carbohydrate content comes from sugars. This includes both sugars that occur naturally in foods (like lactose in milk) and any added sugars.

No, the traffic light system, typically found on the front of packaging, colour-codes fat, saturated fat, sugars, and salt, but not total carbohydrates.

You can check the ingredients list. Ingredients are listed in descending order by weight. If you see sugar, glucose syrup, fructose, or any other type of sugar high on the list, it's a good indication of high added sugar content.

Fibre is a beneficial carbohydrate that doesn't impact blood sugar in the same way as starches and sugars. It's important to read the fibre content to ensure a balanced diet, and its separate listing on UK labels makes this easy to track.

For comparing different products, always focus on the 'per 100g' values. This gives you a standard measurement for a fair comparison. 'Per portion' values can be misleading, as manufacturers' definitions of a portion may vary and could be smaller or larger than what you typically consume.