UK Traffic Light Food Labels: Colours, Portions and Reference Intakes

The colours belong to particular nutrients

The NHS food-label guide describes front-of-pack colour coding for fat, saturated fat, sugars and salt: red means high, amber medium and green low. Read which nutrient each box names. A red salt box is not a statement that every nutrient is high, and a green box is not an ingredient or allergy approval.

Many packs have a mixture of colours. Use the information for the question you are solving—such as comparing salt between otherwise suitable foods—then check the rest of the label. The colours are a quick guide, not a score that certifies one product as best for every person.

This article explains the UK consumer-label context in the NHS guide. It does not provide a complete statement of food-labelling law or generate official traffic-light labels. Imported products and other markets may use different systems.

Find the front portion and the back comparison basis

NHS explains that front labels commonly show energy, fat, saturated fat, sugars and salt for a serving or portion, and may also show per 100 g or per 100 mL information. The manufacturer’s portion can differ from the amount you intend to use.

The back or side nutrition table provides per 100 g or per 100 mL information and sometimes per-portion values. To compare two similar foods at equal weight, use their matching per 100 g rows. For two drinks, use matching per 100 mL rows. Do not mix grams and millilitres without appropriate information.

The number for the amount you use is a separate question. Scale the matching nutrient quantity by your amount, keeping the preparation state and units the same. You do not need to eat 100 g just because that is the comparison basis.

Look at actual headings and footnotes. Dry and prepared foods are different states; a ready-meal column or serving may have its own defined amount. The cereal guide supplies a real UK manufacturer example where equal piece counts have different weights.

A smaller displayed number can belong to a smaller portion

These two foods and values are invented arithmetic examples. They are not measured products and do not assign traffic-light colours or define the rules that produce a front-label colour.

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Both conclusions about sugars are true: B has less per 100 g, and A has less in its smaller declared portion. The same quantity check applies to the salt figures. State which question you answered instead of treating the front number as a universal ranking.

For another known amount, the equation is nutrient amount = per 100 g figure × food amount in grams ÷ 100. Use per 100 mL with an amount in millilitres instead. Label figures can be rounded; show sensible estimate precision rather than implying a laboratory measurement.

Reference intake is not a gram amount or your personal requirement

A reference-intake percentage places the labelled amount in a daily reference context. NHS describes reference intakes as guidelines about approximate amounts of nutrients and energy for a healthy diet. Keep the stated portion with the percentage.

If a fictional box says “12% RI” for salt, that is not 12 g salt, not 12% of the food’s weight, and not a statement that you personally need 12% of the packet. Find the salt gram amount and the portion definition for your calculation. The percentages for different nutrients are not ingredients to add.

The NHS table’s sugars heading is total sugars. It is not a separate US added-sugars declaration. FDA’s US label guide describes Daily Values and total-versus-added sugar rows in its own system. Do not assign a US%DV interpretation or threshold to a UK%RI box.

Individual requirements and prescribed dietary plans are separate from general label references. This guide does not set calorie requirements, a medical salt limit or a breakfast target.

Mixed colours, absent colours and drinks need their own checks

NHS suggests using the front colours to compare similar products, generally looking for more greens and ambers and fewer reds. Keep the nutrient being compared and the relevant whole-label checks visible; a single colour does not settle taste, price, ingredients or personal suitability.

If a pack has no colour coding, that does not establish that it is low in every nutrient. Read the available nutrition table and actual amount. Some front labels supply numbers or reference information without the same colour display.

NHS gives general high/low figures per 100 g for foods, but explicitly says different criteria are used for drinks. Do not copy a food’s sugar threshold onto a drink or infer a colour from an unmatched per-portion number. This page does not supply drink thresholds or a complete colour-calculation algorithm.

Check the ingredients and relevant allergen information separately. Nutrient colours cannot certify an allergy-safe food. If your task is unresolved by the actual label, ask about the exact product or use a suitable known alternative rather than treating a colour as clearance.

Finish with one verifiable sentence: “B has 8 g total sugars per 100 g in these fictional data, while A has 10 g.” That is a specific comparison with an explicit basis. It does not claim that B is the best food overall.

Four checks for a quick shopping comparison