Traffic light labels explained, and what the pack leaves out

No. Traffic light labelling is voluntary in the UK, so no manufacturer has to put the colours on a pack. When they do, red on a food means more than 17.5g fat, 5g saturates, 22.5g sugars or 1.5g salt per 100g. The part the law requires is the nutrition panel on the back.

Is traffic light labelling mandatory or voluntary in the UK?

Voluntary. The government guidance behind the scheme says so twice: front of pack information remains voluntary, and it is for each business to decide which foods it will be most useful on. Most major supermarkets and many manufacturers use it anyway.

The back of the pack is a different matter. Nutrition information has to be declared on prepacked food, covering energy, fat, saturates, carbohydrate, sugars, protein and salt. Front of pack colours can never be given on their own; they sit on top of that mandatory panel.

Who sets the traffic light thresholds?

A group of government bodies, in guidance rather than in a law of its own. The guidance was developed by the Department of Health, the Food Standards Agency and the devolved administrations in Scotland, Northern Ireland and Wales, working with the British Retail Consortium. It follows UK Health Ministers’ recommendation on colour coding and sits under retained Regulation 1169/2011 on food information to consumers. That November 2016 document is still the one businesses are pointed to from the FSA’s nutrition labelling page, last updated on 25 June 2026.

The low cut offs weren’t invented for the scheme. They are lifted from the low nutrition claims in retained Regulation 1924/2006, which is why green for fat is the same 3g per 100g that lets a product legally call itself low fat.

What are the red, amber and green cut offs?

For food, per 100g. Energy is shown but never coloured.

The per portion column only comes into play for portions bigger than 100g.

Drinks follow the same structure per 100ml, at roughly half the levels, with the per portion column applying to servings over 150ml.

Where do the traffic light numbers come from?

They are percentages of an adult’s daily reference intake, which makes them easier to remember. For food, red per 100g means more than 25 per cent of the reference intake in 100g, and red per portion means more than 30 per cent of it in one serving. For drinks the two triggers are 12.5 per cent and 15 per cent.

The reference intakes, set in Annex XIII of retained Regulation 1169/2011, are 8,400 kJ or 2,000 kcal of energy, 70g fat, 20g saturates, 90g sugars and 6g salt. A quarter of 70g of fat is 17.5g, the red line for fat. A quarter of 6g of salt is 1.5g, the red line for salt. Thirty per cent of 6g is 1.8g, the per portion red.

They are adult values, and for fat, saturates, sugars and salt they are maximums not to be exceeded rather than targets to hit. There is no children’s version in the Regulation.

You don’t need to do any of that sum at the shelf. It only explains why the lines sit where they do.

Who decides the portion size on the front of the pack?

The manufacturer. The percentages and any per portion colours on the front are worked out on a portion the company chose. The guidance recommends one that is easily recognisable by and meaningful to the consumer, gives a quarter of a pie or one burger as examples, and says generally accepted portion sizes should be used wherever possible. That is a recommendation. No portion size is fixed in law behind the front of a pack.

So two near identical products can look quite different. Halve the stated portion and every gram figure and every percentage halves with it, and a per portion red can drop to amber. Nothing improper has happened; the numbers are true for the portion declared.

The fixed point is the per 100g column on the back. Nutrition claims such as low fat and low salt are pinned to 100g or 100ml too, so that column is the one that compares like for like across brands.

What does it mean if a product has no traffic light label?

It means someone decided not to use one. Some foods are exempt from nutrition labelling altogether, and the guidance would not expect to see colours on those. Everything else is a choice, and the guidance encourages manufacturers and retailers to use the colours on as many products as possible, because how widely they appear affects whether shoppers notice them.

If a comparable product on the same shelf carries colours and this one doesn’t, turn it over and read the panel yourself. That is the information the law guarantees you.

How do you use traffic light colours when you shop?

1. Read per 100g, not per portion, whenever you compare two products.
2. Check the portion the front is based on before you trust any percentage. If it is a third of a jar, the figures are for a third of a jar.
3. Amber is not a warning. It means the product is neither high nor low in that nutrient, and most everyday food sits there.
4. Red is not a ban. The British Nutrition Foundation is clear that red means high in that nutrient, not that you cannot eat it.
5. No label means read the back. It is mandatory and it is standardised.

The colours cover fat, saturates, sugars and salt. They say nothing about fibre, the nutrient most of us are short of: UK adults are advised to eat 30g a day and most manage about 20g, a shortfall covered in the UK fibre gap. If you check one number the colours leave out, make it fibre per 100g, then read the ingredients, which how to read an ingredients list walks through.

The colours say nothing about the words printed beside them either. Those come under a separate set of rules, covered in does gut friendly mean anything on a UK food label. To try all of this on real packs, take the label test quiz.

When is the label not the question?

When you have symptoms. Front of pack colours are for choosing between two similar products, nothing more. If you have a persistent change in bowel habit, bleeding, unexplained weight loss, difficulty swallowing or pain that wakes you at night, speak to your GP, or contact NHS 111 if you cannot get seen and you are worried.