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Understanding Food Labels

What are food labels and why use them?

Food labels show us information about what foods and drinks contain. It’s important you know where to find the information you need and what to look for.


The current laws around food labelling in the UK outline what information must be provided and how that information must be presented. Food labelling should be clear, easy to read and not misleading. But, the nutrition labelling rules do not apply to food supplements or natural mineral waters.


Using these food labels when shopping can help you make healthier choices, for example, by choosing foods and drinks that are:

  • Lower in saturated fat
  • Lower in sugar
  • Lower in salt
  • Lower in calories


Looking at the nutrition information on food labels can help you make healthier choices. Traffic light labelling allows you to make comparisons between products that are high, medium, or low in fat, saturated fat, salt and sugar. Calories are also shown on the label.


Zoe Hill, Nutrition Scientist, British Nutrition Foundation

Understanding front-of-pack labelling

In the UK, putting nutritional information on the front of pre-packaged foods and drinks is voluntary but most major supermarkets and many food manufacturers provide this.


The information must be displayed as either: Energy (kJ and kcal) only or Energy (kJ and kcal), Fat, Saturated fat, Sugars (total sugars) and Salt. This information will be written per 100g/100ml, per portion or both.


The government’s recommended format is red, amber, green colour-coding, and percentage reference intakes (RIs), or as it is also known - traffic light labelling!

Key facts about food labels

  • The UK laws around nutrition labelling outline what information must be provided to you when buying food and how that information must be presented on the back-of-pack.
  • Front-of-pack labelling in the UK is voluntary but most major supermarkets and many food manufacturers provide this and use the government’s recommended format of red, amber, green colour-coding, and percentage reference intakes (RIs), or as it is also known - traffic light labelling!
  • Allergens will be listed and emphasised in the ingredients list.

Traffic light labelling

Using front-of-pack labels is useful when you want to quickly compare different food products.

When choosing between similar products, try to opt for more greens and ambers, and fewer reds!

What does green mean?

If there is mostly green on the label, then it is low in that nutrient and a healthier choice!

What does amber mean?

This means the product is neither high nor low in the specific nutrient.


You can eat foods with all or mostly amber on the label most of the time.  

What does red mean?

Red does not mean you cannot eat the product, but means the food is high in fat, saturated fat, salt, or sugar.


We should be cutting down on foods with lots of red on the label, or if they are eaten, to have less often and in small amounts.

What are the guidelines for a front-of-pack label?

The table below shows how high, medium, and low levels of fat, saturates, total sugars and salt in foods are classified for front of pack labels (there are different levels for drinks). These levels have been decided by the UK government. The 'per portion' in red is used where portions are 100g or more.


Alongside these traffic lights, the label might also show the amount of these nutrients in a portion of the food or drink and the percentage of your reference intake (RI). If there isn’t much room on the label, just energy values will be displayed but the full nutrition information will be available on the back of the pack.

Understanding back-of-pack labelling

Most pre-packed products must provide a nutrition label on the back of the pack.


By law back of pack nutrition labels must include:         

This will be displayed:                       


…in calories (kcal) and kilojoules (kJ)

Fat content

…in grams (g)

Saturated fat content

…in grams (g)                 

Carbohydrate content

…in grams (g)

Sugar content

…in grams (g)

Protein content

…in grams (g)

Salt content

…in grams (g)

This back-of-pack information must be displayed as per 100g or 100ml of the product but may also be displayed as per portion. Generally, this information will be displayed like the example below:

Typical values

100g contains

Each slice (typically 44g) contains










of which saturates






of which sugars










On top of the above seven values that must be on a nutrition label by law, you might also see extra voluntary information on:

  • Fibre
  • Starch
  • Mono/polyunsaturated fats
  • Polyols (used as sweeteners)
  • Any vitamins or minerals.


Nutrition labelling terms explained


The amount of energy in a food or drink is measured in calories. You'll see on labels, the calorie content is given in kcal and kJ, which are short for kilocalories and kilojoules. Kilocalorie is another word for the well-known ‘calorie’ and kilojoules is the metric measurement of calories.


Carbohydrates include both starch that you find in bread, pasta, rice and potatoes, and sugars; any sugar that has been added by the manufacturer and the sugar that is found naturally.


Of which sugars’ refers to how much of the carbohydrate content of the food or drink comes from sugars (the rest being from starch). ‘Total sugars’ are declared on food labels. Total sugars include both the sugars found naturally in foods and drinks and added sugars. For example, looking at a plain yogurt, it may state it contains 9.9g of total sugars. However, none of these have been added as they all come naturally from the milk.   


This includes both saturated fat and unsaturated fat. If you look at the ‘saturates’ content, you can work out how much of the fat in the product is ‘saturated’ (the fat we should be cutting down on) and ‘unsaturated’ (the fat we should be replacing saturated fat with). It is important not to eat too much saturated fat as this can increase the level of cholesterol in your blood. 


This is the total protein content of the food. The body needs protein to grow and repair itself. Most adults in the UK get more than enough protein for their needs.


The term ‘salt’ on food labels includes all the sodium in a food. While most sodium comes from salt, some can be naturally occurring in food. It can also come from raising agents and additives.

What are reference intakes?

Reference intakes (RIs) have been set by European law and are based on an average sized woman doing an average amount of physical activity. RIs are not targets for people to consume but a guideline to help you make healthy dietary choices and balance your daily intake.

The % RI on the label gives you more information about how much of an average adult’s daily intake limit of each nutrient is in a portion and will help you put it in the context of a healthy, balanced diet.


As part of a healthy, balanced diet, an adult's RIs for a day are:

Energy or Nutrient

Reference Intake 















 *This figure is for total sugars which include free sugars, plus sugars from milk and sugars contained in fruit. Remember, as adults we should be consuming no more than about 30g of free sugars per day.

What about fibre?

You may have noticed that there isn’t an RI for fibre. This doesn’t mean it isn’t important, we’re recommended to eat 30g per day and most people in the UK need to eat more fibre. Fibre can still be included in nutrition labels on the back of packs, and you may see labels like ‘source of fibre’ or ‘high in fibre’ on foods that provide significant amounts. 

Understanding allergy information

It is important that people with food allergies have all the information they need to quickly decide whether a food is suitable for them to eat. To ensure this is the case, there are labelling laws in place to make it easier for you to check what’s in products.


There are 14 common allergens which, when present in a pre-packed product, must be emphasised clearly in the ingredients list, so it stands out from the other ingredients. They can be highlighted, underlined, using bold or italics, different colours or CAPITAL LETTERS.


If it isn’t obvious whether an ingredient contains an allergen, this must be made clear. For example, tofu is made from soya beans, so if a product contains tofu, they must emphasise that it will contain soya: ‘tofu (soya)’.

The ‘contains’ box

Previously food packs used to show a box listing all the allergens the food contained. However, under current law, this isn’t allowed. This is to make sure that people always check the ingredients list to be certain the food is safe for them to eat. Some companies are adding a statement to direct consumers to the ingredients list when checking for allergies, for example:


Allergy Advice: For allergens, see ingredients in bold.


May contain


Some products also state that they ‘may contain’ nuts or seeds. This is because, even though nuts or seeds were not included deliberately as ingredients, there may be traces of them due to use of nuts or seeds where the food was produced. 


For some people, even traces of nuts can still trigger a serious allergic reaction. So, people with nut or seed allergies should avoid products with ’may contain’ labelling, to be on the safe side.

What is ‘Natasha’s Law’?

From 1 October 2021, changes to allergen labelling requirements, also known as Natasha’s Law, came into force for food that is prepacked for direct sale. This refers to food which is packaged at the same place it is offered or sold to consumers and is in this packaging before it is ordered or selected, such as sandwiches, bakery products and fast food.

Prepacked for direct sale food must have a label that displays the name of the food and a full ingredients list, with allergenic ingredients emphasised within it, to help people make safer choices.

What are nutrition and health claims?

Nutrition claims

These relate to what a product does or doesn’t contain or contains in a higher or lower amount. For example:

  • ‘Sugar free’ (must contain less than 0.5g sugars per 100g)
  • ‘Low fat’ (must contain less than 3g fat per 100g)
  • ‘High in fibre’ (must contain at least 6g fibre per 100g)
  • ‘Source of vitamin D’ (must contain at least 15% of the RI for vitamin D per 100g)

You can have a look at the full list of Nutrition Claims permitted for use on foods sold within Great Britain on the UK government website here.

Health claims

These are claims that state or suggest there is a relationship between a product and health. For example:

  • “Calcium is needed for the maintenance of normal bones”.
  • “Potassium contributes to the maintenance of normal blood pressure”.
  • “Vitamin C contributes to the reduction of tiredness and fatigue”.
  • “Folate contributes to maternal tissue growth during pregnancy”.

Health claims on food labels are not allowed to state that the food can prevent, treat, or cure any disease or medical condition. They are also not allowed to refer to a rate or amount of weight loss.

What other information will I find on food labels?

As well as nutritional information, food labels also provide other information about foods and drinks.

List of ingredients

If a food or drink product has two or more ingredients, they must all be listed. These ingredients are listed in descending order of weight. This means the main ingredients in the packaged food will always be displayed first. This can help you to make healthier choices too, as if the first few ingredients in a food or drink product are ‘sugar’ or ‘butter’, you will know that they are the main ingredients, and is therefore a high-fat or high-sugar product.  

Food additives

Different kinds of food additives are used in foods:

  • E numbers - An ‘e number’ shows that a food additive has been safety tested according to the rules set out by the European Commission and has been approved for use in foods.  
  • Antioxidants - Such as vitamin E (E307) are often used in foods containing fat, to stop the fat going off (becoming rancid). Other commonly used antioxidants in foods include vitamin C, also known as ascorbic acid or E300.
  • Preservatives – These are used to stop food going off and to keep it safer for longer (extend its shelf life). For example, sulphur dioxide (E220) is added to dried fruit to stop mould growing on it and meats like bacon and ham are often cured with nitrates (E252) to prevent bacteria growing.
  • Flavour enhancers - These are used to enhance or 'boost' flavour in a food but do not provide flavour themselves. Monosodium glutamate (MSG – E621) is a very common flavour enhancer. Whilst flavour enhancers have E numbers, flavourings do not and instead 'flavouring' will be listed on the ingredients.
  • Sweeteners – These are often used to add a sweet taste in low calorie products like drinks or yoghurts. Common sweeteners include aspartame (E951), saccharin (E954) and acesulfame-K (E950).
  • Emulsifiers – These allow fat and water to mix, when naturally they would separate, e.g., in mayonnaise. A common emulsifier is Lecithin (E322), which is found naturally in many foods. Stabilisers such as locust bean gum (E410) made from carob beans, help to keep these mixtures from separating again.
  • Gelling agents - Such as pectin (E440), which is a type of soluble fibre present in fruit such as apples, provide texture to a product, and thickeners add body to products such as sauces and soups.
  • Colours - These are added to provide colour and make food appear attractive. Some food colourings come from natural sources such as curcumin from turmeric (E100), while others like sunset yellow (E110) are artificial.

These colours include:

  • Sunset yellow (E110)
  • Quinoline yellow (E104)
  • Carmoisine (E122)
  • Allura red (E129)
  • Tartrazine (E102)
  • Ponceau 4R (E124)

These colours are used in several foods, including soft drinks, sweets, cakes, and ice cream, but now several retailers and manufacturers have removed these colours from their product ranges. If any of the six colours listed above are in food or drink, the food label must also have a specific warning saying that the colour 'may have an adverse effect on activity and attention in children’.

Did you know?

If your child shows signs of hyperactivity or attention deficit hyperactivity disorder (ADHD), eliminating some colours from their diet might have beneficial effects on their behaviour.

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Please note that advice provided on our website about nutrition and health is general in nature. We do not provide any individualised advice on prevention, treatment and management for patients or their family members.