How the UK’s Traffic Light Food Labels Actually Work
Parmesan and Cod (raw) couldn’t look more different under the UK’s traffic light system. Parmesan comes out red on fat, red on saturated fat, and red on salt, three reds out of four. Cod comes out green on every single one. But it’s worth being precise about what that actually means: the colours aren’t one overall verdict on a food, they’re four separate, independently calculated ratings, one per nutrient, and each has its own exact gram threshold behind it.
Four nutrients, each judged on its own
The UK’s front-of-pack traffic light system covers four nutrients: fat, saturated fat, labelled “saturates” on most packaging, total sugars, and salt. Energy, in kcal and kJ, is shown alongside them but doesn’t get a colour of its own. Each of the four gets its own green, amber or red rating, worked out from its own real gram content per 100g, completely independently of the other three, which is exactly why a food like Parmesan can be red on three nutrients and still green on sugar.
The exact thresholds, per 100g
Fat: green at 3g or less, amber above 3g up to 17.5g, red above 17.5g. Saturated fat: green at 1.5g or less, amber above 1.5g up to 5g, red above 5g. Total sugars: green at 5g or less, amber above 5g up to 22.5g, red above 22.5g. Salt: green at 0.3g or less, amber above 0.3g up to 1.5g, red above 1.5g. These are the same real UK Government-recommended thresholds our own traffic light labels use, not a rounder, simplified version.
Voluntary, not a legal requirement
Unlike the nutrition claim thresholds covered in our other articles, this specific scheme isn’t a legal requirement. The back-of-pack nutrition table is mandatory under UK food information law, but the colour-coded front-of-pack labels are voluntary, recommended by the UK Government in June 2013 rather than mandated by regulation. That mandatory back-of-pack table is always given per 100g rather than your own real portion, see Why the Calories on a Label Never Match What You Actually Eat for how to scale it to what you actually eat. In practice, every major UK supermarket has adopted it anyway, which is a large part of why the colours feel like a familiar, standard part of UK food packaging even without a legal requirement behind them.
The two real foods above, worked out
Cod (raw) sits at 0.7g fat, 0.1g saturates, 0g sugar and 0.18g salt per 100g, comfortably under every green threshold above, which is why every one of its four labels comes back green. Parmesan sits at 25.8g fat, 17.3g saturates and 1.6g salt, each one over its own red threshold, but only 0.8g sugar, well under 5g, which is why it stays green on that one nutrient alone even while reading red on the other three.
Where you will see it used on this site
Every food page on this site, including Parmesan and Cod (raw), shows its own real traffic light labels worked out directly from that food’s own stored fat, saturates, sugar and salt figures, using these same UK Government thresholds. It’s the one Diet & Nutrition feature on this site that isn’t a single badge, four separate, real colours, side by side, for every food in our database.
*This article is general information, not legal advice. Food labelling law and guidance change over time, so check an official source directly if you need this for your own business’s compliance.
Sources
- Check the label (GOV.UK, Food Standards Agency guidance)
- Guide to creating a front of pack (FoP) nutrition label for pre-packed products sold through retail outlets (Department of Health, Food Standards Agency and devolved administrations)