Is ‘hidden sugar’ a particular health risk? Are some sugars healthier than others? How much sugar should we be consuming?

This article answers these and other questions and points to evidence for the health risks of a high-sugar diet.

  • Action on Sugar
  • Is the ‘harmful sugar’ just the sugar we add to tea and coffee?
  • Is ‘hidden sugar’ a health risk?
  • Might the health risks from sugar be exaggerated?
  • Are some sugars better for us than others?
  • How much sugar should we be consuming?
  • Sugar Tax
  • Examples of sugar levels in food and drink
  • Conclusions


Action on Sugar, launched in the UK in 2014, is an organisation that aims to create sustainable policies and systems that help us reduce our consumption of ‘free sugars’. Supported by expert medical advisors, Action on Sugar works with the government and with the food and drinks industry to agree that a high sugar diet is harmful to our health. Its main objective is to bring about a reduction in the amount of sugar in processed foods. 


Free sugars (usually sucrose) are found in foods such as sweets, cakes, biscuits, chocolate, and many fizzy drinks and juice drinks.

 Hidden sugars (sucrose and other sugars such as dextrose, fructose, and lactose) can be found where you might not expect them: low-fat dairy, sauces, bread, cereals, mayonnaise, savoury pastries etc. 


Is the ‘harmful sugar’ just the sugar we add to tea and coffee?

No, harmful sugar is just one type of sugar – sucrose – which comes from sugar cane or sugar beet. There are other types of sugar, like glucose (from carbohydrates), fructose (from fruits) and lactose (from milk).

Some sugars occur naturally, for instance in fruit. However, other sugars are often added to food, and today, most soft drinks, fruit drinks and energy drinks contain added sugar. See the poster at the end of this article for examples of the sugar levels in commonly consumed foods.

Corn syrup in processed foods

High-fructose corn syrup in particular is an ingredient in many processed foods such as biscuits, ice cream, cereal bars, yoghurt drinks, cakes, pastries, bread rolls and cereals. 

A pot of low-fat fruit-flavoured yoghurt can contain up to ten teaspoons of fructose-based sweetener.


Hidden sugars 

Sugar is also found in food that you may not think of as sugary, such as soups, cereals, tomato ketchup and coleslaw. A 2016 US study reports that ultra-processed foods (containing additives like flavouring, colourants, sweeteners and emulsifiers) often have a particularly high sugar content.


Most food labelling in the UK specifically identifies how much of the carbohydrates in a product is made up of sugar. It is in the small print – but it is worth checking.

Many products advertised as ‘low fat’ contain high levels of sugar.  



Is ‘hidden sugar’ a health risk?

We may be consuming a lot more sugar than we realise, which makes it important to know how harmful sugar really is. Is it, as American Professor Richard Johnson claims, ‘an environmental toxin with major health implications’? Research in recent years has linked sugar with a range of serious health risks and illnesses.

Evidence suggests that the four main health risks associated with sugar are:

  • Type 2 diabetes
  • High blood pressure
  • Excess body weight and obesity
  • Coronary heart disease 

Type 2 diabetes

Consuming sugar-sweetened drinks regularly is associated with a greater incidence of type 2 diabetes. That was the conclusion of an analysis of 17 studies, published in the British Journal of Sports Medicine in 2016.

High blood pressure

Sugar-sweetened drinks such as sodas/soft drinks, non-100% fruit juice drinks, syrup-based drinks, sports and energy drinks, chocolate milk, yogurt drinks, Coca-Cola, Sprite etc., were significantly associated with raised blood pressure. That’s the verdict from a 2020 review of published research, which concluded that high consumption of sugar-sweetened beverages increased systolic blood pressure and hypertension in children and adolescents.

Excess body weight and obesity

The US government Office of Disease Prevention and Health Promotion reports, ‘Strong and consistent evidence shows that intake of added sugars from food and/or sugar-sweetened beverages are associated with excess body weight in children and adults.’

Exception: A 2012 systematic review advised that excess body weight in children and adults may not apply in relation to one type of sugar. ‘Fructose does not seem to cause weight gain when it is substituted for other carbohydrates in diets that provide a similar level of calories.’ This suggests that the risk in relation to fructose is related to consumption leading to increased calorie intake.

Coronary heart disease (including heart attack and stroke)

In 2017 the American Heart Association issued a Scientific Statement which concluded that strong evidence supports the association of added sugars with increased cardiovascular risk in children. This is supported by a 2021 review of published cohort studies, which found that the habitual consumption of sugar-sweetened beverages was associated with a higher risk of cardiovascular disease and death in a dose–response manner i.e., the greater the consumption, the greater the risk.

A 2011 article in the European Journal of Internal Medicine highlighted, ‘how an excess of dietary carbohydrates, particularly fructose, alongside a relative deficiency in dietary fats and cholesterol may lead to the development of Alzheimer’s Disease. However, a study published in 2017 suggests that it is artificially sweetened drinks which are associated with an increased risk of Alzheimer’s.


Might the health risks from sugar be exaggerated?

Some commentators believe so. Here are some of their reasons:

  • It is probably simplistic to blame sugar alone for such a range of diseases. The situation is most likely more complicated than that. As NHS Choices points out, other dietary factors may be at work, such as fat and salt and, as we have reported elsewhere on Age Watch, lack of exercise may also be implicated.

  • Fructose is associated with a range of serious medical conditions but clinical trials have yet to prove beyond all doubt that it causes them. This is a point made by the Senior Editor of Harvard Health in 2011.

However, this argument in ‘defence’ of sugar is usually relative rather than absolute and typically sees sugar as one of many health risks rather than the only one.


Are some sugars better for us than others?

The sugars which occur naturally in most fruit grown in the UK (fructose) seem healthiest, as they have a relatively low glycaemic index. Eating whole fruits is healthy because of the fibre they contain, particularly in the skins. This fibre slows the rate at which the natural sugars are absorbed by the body.

Conversely, sugar-sweetened drinks have a high glycaemic index and are associated with a number of health risks. In addition, these drinks don’t make us feel full in the same way as more solid forms of sugar, making it easier to consume too much sugar and become overweight. 


The glycaemic index (GI) is a rating system for foods containing carbohydrates. It shows how quickly each food affects your blood sugar (glucose) level.


How much sugar should we be consuming?

A maximum of 5% of our energy should come from free sugars – i.e., from the sugars added to fruit and drinks – together with the sugars found naturally in honey, syrup and unsweetened fruit juices, smoothies and purees. This is roughly equivalent to consuming seven sugar cubes a day. That’s the advice from the NHS.

The NHS advises that we don’t need to cut down on sugar found naturally in milk, fruit and vegetables, but we should remember these sugars are included in the ‘Total sugar’ figure found on food labels.


Sugar Tax 

In 2018 the UK government introduced the Soft Drinks Industry Levy – also known as the Sugar Tax – which taxed soft drinks containing at least 5g of sugar per 100ml. This was intended to encourage the soft drinks industry to reduce the sugar content of their soft drinks, and therefore to help reduce levels of obesity in the country.

Despite criticisms from opponents, this initiative appears to have had some success. One 2021 study reported that although the total volume of soft drinks purchased in the year after the introduction of the sugar tax didn’t change, sugar consumption fell by an average of 9.8%.


Examples of sugar levels in food and drink

These examples of common foods and drinks show their approximate sugar content as the equivalent of 4g sugar lumps.