This piece was written by one of our contributors: dietician – Maeve Hanan
Many people are understandably worried about the impact of consuming sugar, as it can sometimes feel like it is public health enemy number one. But nutrition is never black and white, so this article will explore the role of sugar and how we can achieve balance in terms of our sugar intake.
What is Sugar?
Sugar is the name that we give to certain sweet-tasting carbohydrates.
Depending on the arrangement of simple sugar units called saccharides, carbohydrates are classified as either:
- Monosaccharide — made up of only one saccharide molecule
- Disaccharide — made up of two saccharides molecules
- Oligosaccharide — made up of up to 10 saccharide molecules
- Polysaccharide — made up of more than 10 saccharide molecules
So although all types of carbohydrates contain these single sugar units, when we talk about sugar in our diet we usually mean ‘simple sugars’ i.e. monosaccharides and disaccharides. For example, the type of sugar found in energy drinks (glucose) is a monosaccharide and table sugar (sucrose) is a disaccharide.
Whereas, ‘complex carbohydrates’ like oligosaccharides and polysaccharides are found in starches and fibres and foods such as wholegrains and pulses. Fruit and vegetables can contain both simple sugars and complex carbohydrates, but in general, fruit tends to contain more simple sugars than vegetables.
In terms of the nutritional role of sugar in our diet, this is divided into two main groups:
- Free sugars i.e. those which are “added to foods by the manufacturer, cook or consumer, plus sugars naturally present in honey, syrups and unsweetened fruit juices” (1)
- Naturally-occurring sugar found in fruit, vegetables and dairy
The Nutritional Role of Sugar
The simple sugar glucose is an important energy source for our body. In particular, our brain needs roughly 120g of glucose per day to function optimally (2).
- A medium slice of bread contains around 15g of carbohydrate
- A medium potato contains around 40g of carbohydrate
- A medium portion of pasta or rice contains around 40 – 45g of carbohydrates
The carbohydrates found in food are broken down in our body to provide the glucose that our body needs for fuel. This is one of the reasons why public health guidelines, like the Eatwell Guide, advise us to include a portion of starchy carbohydrate-based food at every meal (3).
Glucose is also our body’s preferred energy source for bursts of activity in our muscles and it is needed to produce an important storage form of energy called glycogen (2). Therefore, carbohydrates play a very important role for athletes, who usually need to consume more carbohydrates than those with lower activity levels. For example, carbohydrates are a key part of pre-exercise and recovery meals, and those who are exercising for more than an hour at a moderate or high intensity level are advised to consume sugar-containing drinks, gels or foods (jelly babies are a popular option) while training in order to improve their performance.
Carbohydrate-containing foods like fruit, vegetables, legumes, dairy and grains also provide a lot of nutritional value beyond carbohydrate alone, and including these foods in the diet is associated with numerous health benefits.
So carbohydrate-containing foods undoubtedly play a vital role within a balanced diet. However, the nutritional impact of sugary foods and drinks is different to that of carbohydrates as a whole.
One of the main risks related to consuming too much sugar on a regular basis is an increased risk of tooth decay (1). This is because the bacteria on our mouth produces an acid when it breaks down sugar, and this acid can dissolve tooth enamel (1).
Consuming a high intake of sugar can also contribute to a higher calorie intake. This can be a useful strategy for those who are aiming to gain weight, whereas those who are aiming to lose weight may want to be more mindful of this. For example, there is some evidence that regularly drinking sugary drinks is associated with weight gain and a higher BMI in children and teenagers (1).
Drinking a lot of sugary drinks is linked with a higher risk of developing type 2 diabetes, which may also be related to a higher intake of calories (1). But on the other hand, sugar can play an important role in the management of diabetes, as when blood glucose levels drop dangerously low (hypoglycemia) a fast-acting type of sugar is needed to bring this up to a safe level again. Those with diabetes who are at risk of hypoglycemia will be given specific advice and a hypoglycemia management plan from their diabetes team.
It’s important to highlight that products sold as ‘natural sugar replacements’ like rice syrup, maple syrup, honey, molasses and coconut sugar are included within the ‘free sugars’ category. This is because they have a very similar nutritional impact as ordinary sugar, and although they may contain some additional vitamins, minerals or antioxidants, these are present in insignificant amounts.
But remember that food gives us more than just nutrition, and it is absolutely valid to appreciate the taste of sugar, or the happy memories involving sweet foods at times of celebration etc.
How Much Sugar is Recommended?
In the UK, those over the age of two are advised to limit their intake of free sugars to 5% of total dietary energy (1).
This works out as (4):
- 5 sugar cubes/teaspoons of sugar per day for 4 – 6 year olds
- 6 sugar cubes/teaspoons of sugar per day for 7 – 10 year olds
- 7 sugar cubes/teaspoons of sugar per day for those aged 11 or older
On average, UK adults seem to be consuming roughly double the recommended amount at 11% of total dietary energy (5).
So although the public health recommendations advise consuming free sugars in relatively small amounts, this doesn’t mean that sugar needs to be avoided completely. Infact, this recommendation shows that sugary foods and drinks can be included within a balanced diet, but it is best to consume these in smaller amounts as compared with foods like grains, starchy foods, fruit, vegetables, high-protein foods, dairy, nuts and seeds etc.
The War on Sugar
Since the 1970’s sugar has been referred to as ‘dangerous’, ‘harmful’, ‘toxic’ and even ‘deadly’. A lot of this began around the time that the book by John Yudkin “Pure, White and Deadly” was released. At this time, a lot of the nutritional focus was on reducing fat intake to promote health, and it was valid to explore the impact of sugar in more detail. However, in a similar way that fat was previously demonised in an overly simplistic manner as being ‘bad’, this has occured to sugar in recent years. Fortunately, the conversation is now starting to shift towards the importance of looking at the bigger picture of whole diet patterns rather than single foods or nutrients.
Discussions related to sugar taxes also had a big impact on the perception of sugar. For example, in the UK in 2018 a soft drinks levy was introduced which involved (6):
- Taxing drinks with a total sugar content of 5 – 8g per 100ml at 18p per litre
- Taxing drinks with a total sugar content of more than 8g per 100ml at 24p per litre
By 2019, reformulation by the soft drinks industry led to a 34% reduction in the amount of drinks available in the UK that contained more than 5g of sugar per 100ml (6).
So although there have been some positive outcomes from the focus on reducing the amount of sugar in our diet, for many people the exposure to a lot of black and white messages about sugar being ‘bad’ has contributed to food anxiety and in some cases a disordered relationship with food. Considering the roughly 7% increase in eating disorder prevalence we are seeing in the UK each year, it is important to be mindful about how we communicate public health messages like this (7).
We also shouldn’t feel guilty for enjoying sugary products; afterall, our sweet tooth is an evolutionary survival mechanism to promote the intake of energy and essential nutrients (8). Consuming sweet foods also stimulates feelings of pleasure in our brain (8).
Of course, there are variations between people as some enjoy sweet tastes more than others. This seems to be influenced by many factors including genetics, ethnicity, medication and exposure to sweet tastes in early life (8). Children also tend to have a stronger preference for sweet tastes than adults overall (8).
Although it is natural and common to enjoy sweet tastes, our food environment has also changed a lot over time and our access to sugary foods is much higher than that of our ancestors. So it is worth exploring public health strategies to improve our food environment, while also acknowledging that sugar can be enjoyed within a balanced diet, as extreme messages that villfiy sugar entirely are likely to do much more harm than good.
The ‘Sweet Spot’
As is often the case when it comes to nutrition, the answer lies in the balanced middle ground. This ‘sweet spot’ when it comes to sugar intake involves acknowledging that too much sugar is usually not a good idea for our health, but at the same time it is entirely normal to enjoy sweet food and sugar can absolutely be enjoyed as part of a balanced diet. After all, we shouldn’t feel guilty for adding a bit of sweetness to our lives!
(1) SACN (2015) “Carbohydrates & Health” [Accessed February 2021 via: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf]
(2) Berg, Tymoczko & Stryer (2002) “Biochemistry 5th edition – Section 30.2: Each Organ Has a Unique Metabolic Profile” [Accessed February 2021 via: https://www.ncbi.nlm.nih.gov/books/NBK22436/]
(3) PHE (2016) “The Eatwell Guide” [Accessed February 2021 via: https://www.gov.uk/government/publications/the-eatwell-guide
(4) Change4Life “Sugar” [Accessed February 2021 via: https://www.nhs.uk/change4life/food-facts/sugar]
(5) PHE (2018) “National Diet and Nutrition Survey Results from Years 7 and 8 (combined) of the Rolling Programme (2014/2015 to 2015/2016)” [Accessed February 2021 via: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/699241/NDNS_results_years_7_and_8.pdf]
(6) Scarborough et al. (2020) “Impact of the announcement and implementation of the UK Soft Drinks Industry Levy on sugar content, price, product size and number of available soft drinks in the UK, 2015-19: A controlled interrupted time series analysis” [Accessed February 2021 via: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003025])
(7) Beat Eating Disorders “Statistics for Journalists” [Accessed February 2021 via: https://www.beateatingdisorders.org.uk/media-centre/eating-disorder-statistics
(8) Drewnowski et al. (2012) “Sweetness and Food Preference” [Accessed February 2021 via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3738223/]