Do we need sugar in our diet?

Sugar is a type of carbohydrate, which provides calories (energy). In the UK, many of us consume a diet that is too high in sugar, which may have negative health implications. This fact sheet will look at:

  • the different types of sugar
  • foods that have a high sugar content
  • the impact of a high sugar diet on our health
  • how to understand food labels

Types of sugar

Sugar is a broad term for a simple carbohydrate. Sugars can be:

  • natural (e.g., found in fruits, vegetables, plants and dairy products)
  • commercially produced in large quantities and added to foods, known as ‘free sugars’

What are free sugars?

‘Free sugars’ is a term used for all sugar added to foods, such as sucrose (table sugar) or glucose. This can be added by the manufacturer, cook or the consumer. It also includes sugars naturally present in honey, syrups and unsweetened fruit juices. 

Sugar found naturally in milk and milk products (lactose), as well as the sugar contained in whole fruit and vegetables (fructose), don't count as free sugars. We do not need to reduce the amount of these products we eat. 

The Scientific Advisory Committee on Nutrition (SACN) recommends that free sugars should account for no more than five per cent of our total daily energy (calories) intake. This is equivalent to:

  • 19g or five sugar cubes for children aged four to six
  • 24g or six sugar cubes for children aged seven to ten
  • 30g or seven sugar cubes for 11 years and over

Sugar in fruit

Whole fruit contains fibre, vitamins, minerals and some natural sugar. These are a healthy alternative to foods high in free sugars and fat. Pure fruit juices and smoothies are often unsweetened, as the sugar comes naturally from the fruit. However, free sugars are released during the juicing process, so intake should be limited to a small 150ml glass, once a day. It will also count towards one of your 5-a-day

Which foods are high in free sugars?

Foods that contain high levels of free sugars are:

  • Sugar-sweetened drinks (including fizzy drinks, juice drinks, energy drinks, squashes and alcoholic drinks)
  • Cereal-based products (biscuits, cakes, pastries and sweetened breakfast cereals)
  • Confectionary (chocolate, chocolate spread and sweets)
  • Dairy products, such as sweetened flavoured milk and yoghurts

Savoury products can also contain some sugar, such as tomato ketchup or pre-prepared sauces. It is important to read food labels to know how much sugar they contain.

Sugar and health

The SACN report (2015) found that high intakes of sugar is associated with greater risk of tooth decay and obesity. Consumption of sugar-sweetened drinks tends to be high in children aged between 11 and 16.

Some research also suggests that drinking sugar-sweetened drinks is linked to an increased risk of type 2 diabetes. This is further increased by the number of sugar-sweetened drinks that is consumed.

The UK introduced a ‘soft drinks industry levy’ (a ‘sugar tax’ on companies making soft drinks) in 2016, where a tax is added to drinks with added sugars. Manufacturers are reducing the amount of sugar added to fizzy drinks and squashes. Look for options which have no added sugar and choose these where possible.

Sugar and weight

A small amount of sugar will not make you overweight. A high-sugar diet may make excess weight gain more likely if overall calorie intake is higher than the body needs. High-sugar diets are not the only cause of weight gain: too many calories from any source will make you put on weight.

Sugary drinks are thought to be the biggest problem, as they tend to be high in free sugars and low in other nutrients and it’s easier to overdo the amount you drink. 

Sugar and tooth decay

High sugar intakes often lead to tooth decay. It is important to avoid frequent sugary drinks and snacks for your teeth and your overall health. 

Free sugars and acids found in pure fruit juices, smoothies and sweetened squash can cause tooth decay. Watch your portion size and have these with a meal. 

'Diet' soft or fizzy drinks have little or no sugar; however, most are still acidic enough to harm your teeth if you drink them too often.

Sugar and food labels

You can get an idea if a certain type of food is high in free sugars by looking at the ingredients list on the packaging. Sugar added to food must be included, and if it is near the top of the list, the food is likely to be high in free sugars.

To confuse matters, sugar is not always listed as ‘sugar’. Other words used to describe sugar can be cane sugar, honey, brown sugar, fruit juice concentrate/purees, syrup, fructose, glucose, treacle, maltose or sucrose.

Reading food labels

Nutritional information must include the amount of sugar in the product, often labelled as ‘of which sugars’. This is the total amount of sugar in the product, not just the free sugars. This information helps us to make healthier choices. The nutrition panel on the back or side of a label will provide information per 100g and/or per portion, which means you can compare like-for-like products.

Some products will provide a traffic light summary on the front of pack:


Low (green)

Medium (amber)

High (red)

High per portion - if more than 100g/150ml (red)

Sugar in food 
(per 100g)

5g or less

between 5g and 22.5g

more than 22.5g


Sugar in drink
(per 100ml)

2.5g or less

between 2.5g and 11.25g

more than 11.25g


A product which is ‘red’ should be eaten with caution and less often. We should be aiming to eat more green and amber products. Find out more about food labelling.


  1. In general, we eat too many free sugars in our diet, with sugar-sweetened drinks being one of the biggest concerns
  2. Too many free sugars in our diet are linked to obesity and tooth decay
  3. Sugar found naturally in milk, fruit and vegetables isn’t classed as free sugar and we don’t need to limit the amount we eat
  4. Always read food labels and aim to eat food and drinks which are classed as low in sugar
  5. If you choose to eat sugary food or drinks, it’s best to have them at mealtimes
  6. Fresh fruit in between meals is a nutritious snack
  7. Water, low-fat milk, or unsweetened tea or coffee are good choices for a drink between meals