UK Food Label Traffic Light System Explained
Walk into any Tesco, Sainsbury’s, or Asda, and you will see those familiar coloured circles on the front of most packaged foods. The traffic light label is one of the most recognisable features of UK food packaging — but do you actually know what the colours mean, and where the system falls short?
What Is the Traffic Light Label System?
The traffic light labelling system is a front-of-pack nutrition label used across the United Kingdom. It uses red, amber, and green colour coding to show at a glance whether a food product is high, medium, or low in four key nutrients:
- Fat — total fat content
- Saturated fat — the type linked to raised cholesterol
- Sugar — total sugars (including natural and added)
- Salt — total salt content
Each nutrient gets its own colour independently. A product might show green for salt but red for sugar, for example. The label also typically shows the calorie count per serving alongside the four colour-coded nutrients.
The idea is simple: the more greens you see, the more often that product can comfortably fit into a balanced diet. More reds suggest it is something to enjoy less frequently or in smaller portions.
Who Created the Traffic Light System?
The traffic light label was developed by the Food Standards Agency (FSA) in the early 2000s and formally recommended in 2006. It was designed to give UK shoppers a quick, visual way to compare products without needing to interpret detailed nutrition tables.
In 2013, the UK Government worked with the FSA and the Department of Health to create a consistent front-of-pack labelling scheme that combined traffic light colours with reference intake (RI) percentages. This hybrid approach is what you see on most UK products today.
The scheme is voluntary — there is no law requiring manufacturers to use it. However, most major UK retailers (Tesco, Sainsbury’s, Asda, Morrisons, Waitrose, Co-op, Aldi, Lidl, and M&S) have adopted it, as have many branded food companies.
Good to know
The back-of-pack nutrition information table is mandatory under UK food law. The traffic light colours on the front are an additional, voluntary aid.
Traffic Light Thresholds: The Exact Numbers
The FSA sets specific cut-off points that determine whether a nutrient gets a green, amber, or red label. These differ for food (per 100g) and drinks (per 100ml), because drinks naturally contain more water and therefore lower concentrations of nutrients.
Thresholds for Food (per 100g)
| Nutrient | Green (Low) | Amber (Medium) | Red (High) |
|---|---|---|---|
| Fat | ≤ 3.0g | 3.1g – 17.5g | > 17.5g |
| Saturated fat | ≤ 1.5g | 1.6g – 5.0g | > 5.0g |
| Sugar | ≤ 5.0g | 5.1g – 22.5g | > 22.5g |
| Salt | ≤ 0.3g | 0.31g – 1.5g | > 1.5g |
Thresholds for Drinks (per 100ml)
| Nutrient | Green (Low) | Amber (Medium) | Red (High) |
|---|---|---|---|
| Fat | ≤ 1.5g | 1.6g – 8.75g | > 8.75g |
| Saturated fat | ≤ 0.75g | 0.76g – 2.5g | > 2.5g |
| Sugar | ≤ 2.5g | 2.6g – 11.25g | > 11.25g |
| Salt | ≤ 0.3g | 0.31g – 0.75g | > 0.75g |
Notice that drink thresholds are roughly half of the food thresholds. This is why a smoothie with 13g of sugar per 100ml gets a red light, even though the same sugar level in a solid food would only be amber.
How to Use Traffic Light Labels in Practice
The traffic light system is most useful when you are comparing similar products. Here is a practical approach:
1. Compare like-for-like
Use the colours to compare two brands of the same type of product. If you are choosing between two pasta sauces, the one with more greens and fewer reds is generally the better choice for everyday eating.
2. Focus on your priorities
If your GP has mentioned watching your salt intake, pay particular attention to the salt colour. If you are managing your weight, sugar and fat colours matter most. You do not need to obsess over every single colour on every product.
3. Check the portion size
Traffic light colours are based on per 100g/100ml thresholds, but the label also shows values per portion. A product might show amber per 100g, but if the suggested portion is 200g, you are actually consuming double the displayed amount.
4. Use it as a starting point, not the final answer
The traffic light system is a helpful quick guide, but it only covers four nutrients. For a more complete picture — including fibre, protein, vitamins, minerals, and additives — you will want to look deeper. This is where understanding the full nutrition label becomes valuable.
Limitations of the Traffic Light System
While the traffic light label is genuinely useful, it has some important blind spots that are worth understanding.
It does not cover additives or E-numbers
A product could show all-green traffic lights and still contain a long list of additives and E-numbers. The system only measures fat, saturated fat, sugar, and salt — nothing about the quality of ingredients or processing methods used.
It ignores micronutrients
Vitamins, minerals, and fibre are invisible to the traffic light system. A product high in iron, calcium, or vitamin D gets no credit for those benefits. Similarly, a product completely devoid of micronutrients can still show green lights if it is low in fat, sugar, and salt.
Portion sizes can mislead
The per-100g thresholds determine the colour, but manufacturers can set their own portion sizes. A biscuit maker might list a “portion” as one biscuit, making the per-portion numbers look modest — even if most people eat three or four.
It does not distinguish between types of fat or sugar
The system treats all fats the same, whether they come from olive oil or hydrogenated vegetable fat. Similarly, natural sugars in fruit get the same red light as added refined sugar. This can create misleading impressions about certain whole foods.
It does not account for ultra-processed food
A product can be heavily ultra-processed with numerous industrial ingredients and still display mostly green traffic lights if the final fat, sugar, and salt numbers are low.
When Green Is Not the Whole Story
Some products appear healthy based on traffic lights alone, but a closer look reveals a more complex picture.
Diet soft drinks
Typically all-green on the traffic light, since they contain no fat, sugar, or salt. However, they often contain artificial sweeteners (such as aspartame or sucralose), acidity regulators, and flavourings that do not appear on the traffic light at all.
“Low-fat” ready meals
Often show green or amber for fat, but may compensate for reduced fat with added sugar, starches, or flavour enhancers. The traffic light system might show improvement in one area while masking deterioration in another — particularly when it comes to ingredient quality.
Breakfast cereals marketed as healthy
Some cereals show amber for sugar (just under the red threshold) and green for fat and salt, but may contain multiple forms of added sugar listed separately in the ingredients (glucose syrup, honey, fructose), plus various additives.
When Red Does Not Mean Bad
Equally, some genuinely nutritious foods trigger red lights. Understanding this prevents you from avoiding foods that could benefit your diet.
Extra virgin olive oil
Shows red for fat (100g of fat per 100g — it is pure fat). Yet olive oil is rich in monounsaturated fatty acids and polyphenols. The NHS and Mediterranean diet research consistently highlight its health benefits when used in moderation.
Cheese
Most cheeses show red for fat and saturated fat. However, cheese is also an excellent source of calcium, protein, vitamin B12, and phosphorus. A 30g portion of Cheddar provides roughly a third of your daily calcium needs.
Nuts and seeds
Almonds, walnuts, and seeds all show red for fat. They are, however, packed with healthy unsaturated fats, fibre, protein, magnesium, and vitamin E. The NHS recommends a small handful of unsalted nuts daily.
Dried fruit
Raisins, dates, and apricots show red for sugar. The sugar is naturally occurring and comes packaged with fibre, iron, and potassium. The NHS counts a 30g portion of dried fruit as one of your five a day — though they recommend eating it with meals rather than between them, for dental health.
The key takeaway
Traffic lights are a useful screening tool, but they work best alongside — not instead of — a broader understanding of food quality. Context matters.
Going Beyond Traffic Lights with NutraSafe
The traffic light system answers a narrow question: is this product high, medium, or low in fat, saturated fat, sugar, and salt? That is genuinely helpful for quick comparisons in the supermarket aisle.
But if you want to understand the full picture — what additives are in your food, how it contributes to your daily vitamin and mineral intake, whether it is ultra-processed, and how it fits into your overall dietary pattern — you need more detail.
NutraSafe’s barcode scanner gives you the traffic light basics plus a complete breakdown of additives, E-numbers, micronutrients, and processing level. You can see at a glance what the traffic light misses.
If you are tracking your intake over time, the food diary and calorie counter logs everything — macros, micros, and ingredients — so you can spot patterns that a quick glance at front-of-pack labels simply cannot reveal.
Practical Tips for Using Traffic Light Labels
- Do not aim for all-green everything. A balanced diet includes foods across all colours. The goal is for your overall intake to be reasonable, not for every individual item to be green.
- Use red as a “check, not a reject” signal. When you see red, ask: is this a nutritious food (like olive oil or nuts) that happens to be high in one metric? Or is this a processed product with little nutritional value beyond calories?
- Compare per 100g, not per portion. Manufacturers set their own portion sizes. Per 100g is the standardised measure that lets you compare products fairly.
- Pair traffic lights with the ingredients list. The colours tell you how much of certain nutrients. The ingredients list tells you what is actually in the food. Both matter.
- Remember what is missing. No colour for fibre, protein, vitamins, or minerals. A food with poor micronutrient content can still look green. Consider the broader nutritional context.
See What Traffic Lights Miss
NutraSafe scans barcodes and shows you the complete picture — additives, E-numbers, vitamins, minerals, and more.
Try NutraSafe FreeFrequently Asked Questions
What do the traffic light colours mean on food labels?
Green means the food is low in that nutrient (fat, saturated fat, sugar, or salt), amber means medium, and red means high. The more green lights, the healthier the choice for that particular metric. The system was developed by the UK Food Standards Agency to help shoppers make quicker, more informed decisions.
Are traffic light food labels mandatory in the UK?
No, traffic light labelling is voluntary in the UK. The back-of-pack nutrition table is mandatory under UK food law, but the front-of-pack colour-coded traffic light label is a recommendation from the FSA. Most major UK supermarkets and many manufacturers have adopted the system voluntarily.
What are the exact thresholds for red, amber, and green on food labels?
For food per 100g: Fat is green at 3g or below, amber from 3.1g to 17.5g, and red above 17.5g. Saturated fat is green at 1.5g or below, amber from 1.6g to 5g, and red above 5g. Sugar is green at 5g or below, amber from 5.1g to 22.5g, and red above 22.5g. Salt is green at 0.3g or below, amber from 0.31g to 1.5g, and red above 1.5g.
Is a food unhealthy just because it has a red traffic light?
Not necessarily. Some nutritious foods like olive oil, cheese, and nuts will show red for fat because they are naturally high in fat, but they contain beneficial fats and important nutrients. The traffic light system is a quick visual guide, not a complete picture of nutritional quality.
Do traffic light labels cover additives and E-numbers?
No, traffic light labels only cover fat, saturated fat, sugar, and salt. They do not show information about food additives, E-numbers, vitamins, minerals, or fibre. For a fuller picture, you need to read the full ingredients list or use a food scanner app like NutraSafe.
Related Reading
Last updated: February 2026. Sources: Food Standards Agency (FSA), NHS, Department of Health front-of-pack nutrition labelling guidance.