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Healthy eating 04 Jun 2021

Good and bad sugar

Free sugar and natural sugar: know the difference

Sugar being poured in a cup

Whatever you eat, sugar can find its way into your diet if you are not careful. In this article you can find out what sugar is, what it does to your body, and how to stay one step ahead.

What is sugar?

Sugar is a simple form of carbohydrate. It is one of the nutrients that powers your body, along with protein and fat. So, some sugars are indeed ‘friendly’: you need them. But when it comes to your health, are all types of sugar equal?

Natural versus ‘free’ sugar

Sugar is actually sucrose, which is made up of glucose and fructose. There are other types of sugars too, including lactose, which naturally occurs in milk. Supermarkets sell a wide range of sugars. But when it comes to your health, there are two types that count:

  • Naturally occurring sugars – sugars that are found in unsweetened dairy products, vegetables, fruit in its natural state (not pulped or juiced) and starchy foods
  • 'Free’ sugars – any sweetener added to foods, including sugar, honey, natural syrups, alternative sweeteners, and any fruit-based product separated from the natural fibre – which includes fruit juice.

Naturally occurring sugars are fine to eat – in fact, you can’t avoid them even in a healthy diet. But the UK’s Scientific Advisory Committee on Nutrition says that we need to drastically reduce our intake of free sugars to less than 5% of our daily calories 1. That's:

  • 30g (7 tsp) for adults and children aged 11 years and over
  • 24g (6 tsp) for children aged 7-10
  • 19g (around 5 tsp) for children aged 4-62.

Why does it matter?

It is well known that sugar intake is linked to body weight3. Excessive weight can lead to obesity, which has a range of associated risks including high blood pressure, heart disease, some types of cancer, and liver or kidney disease4. It can also lead to Type 2 diabetes, which can cause blindness, heart disease, kidney failure, stroke and foot problems causing more than 135 amputations per week in the UK5. Research has also found a separate link between sugary drinks and diabetes6. Sugar also causes tooth decay, which can lead to a surprising level of ill-health including septicaemia, and is the leading cause of hospitalisation of 5-9 year olds7.

"Your sugar intake is in your hands – and the guidance is almost disappointingly simple: keep to foods that are as natural and unprocessed as possible, and limit sweet foods other than fruit."

How does sugar affect your body?

The evidence is overwhelming – so why it is so hard to stay away from the stuff? When your body receives a hit of sugar, it reacts by producing the hormone insulin, which tells your body to store the sugar for energy. It also produces dopamine – a feel-good hormone that makes you feel elated. After a short time, the sugar high is replaced with a slump – leaving you wanting more."

It’s hard, as sugar is freely available in most of the foods we eat – and we start young, from baby snacks sweetened with fruit juice. Over time, if the body regularly receives excessive sugar, this can lead to long-term health problems.8

What can you do about it?

Your sugar intake is in your hands – and the guidance is almost disappointingly simple: keep to foods that are as natural and unprocessed as possible, and limit sweet foods other than fruit.

This series will look in more detail at how you can to reduce your sugar intake and keep yourself and your family healthy. Tackling something so embedded in your life can feel overwhelming, but if you focus on one small step, it’s surprising what you can achieve.

Make a change this week!

  • Fill in a food diary for a week to identify what you could change.
  • Identify easy wins – can you reduce the sugar in your tea by one spoonful, or replace soft drinks with water?
  • Check packets to see sugar levels – you may be surprised where it’s lurking.
  • Fill the fruit bowl with your favourite fruit and vegetables to tempt you away from other snacks.
  • If you find it hard to resist sugar, it only takes 21 days to break the habit.

The next article will look at alternatives to sugar and ask, are they too good to be true?

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1. Public Health England 2015. Why 5%? ( last accessed in June 2021

2. BDA Food fact sheet: Sugar ( Updated March 2017), last accessed in June 2021

3. The BMJ (, last accessed in June 2021

4. NHS (, last accessed in June 2021

5. Diabetes UK (, last accessed in June 2021

6. The BMJ ( and Diabetes UK (, last accessed in June 2021

7. Royal College of Surgeons (, last accessed in June 2021

8. Diabetes UK (, last accessed in June 2021