The World Health Organization (WHO) is appealing to people to reduce the amount of sugar they are consuming.

A new guideline from the WHO recommends that both adults and children should reduce their daily intake of free sugars to less than 10% of their total energy intake, while reducing to below 5% - roughly six teaspoons of sugar per day - would be even more beneficial.

It noted that one can of sugar-sweetened fizzy drink contains up to 10 teaspoons of free sugars.

"We have solid evidence that keeping intake of free sugars to less than 10% of total energy intake reduces the risk of overweight, obesity and tooth decay," commented Dr Francesco Branca of the WHO.

Free sugars are the monosaccharides, such as glucose, and the disaccharides, such as table sugar, that are added to foods and drinks by consumers, cooks and manufacturers. They also include the sugars naturally present in fruit juices, fruit juice concentrates, syrups and honey.

The new guideline does not count the sugars found in fresh fruit, fresh vegetables and milk as there does not appear to be any adverse effects linked to the consumption of these.

The WHO pointed out that a lot of the sugar people consume today is ‘hidden' in processed foods that people would not necessarily think of as containing sugar. For example, one tablespoon of tomato ketchup contains around one teaspoon of free sugars.

The WHO made its recommendation based on an analysis of the latest scientific evidence, which clearly shows that increasing amounts of sugar in the diet are associated with weight gain.

Furthermore, children who consume the highest amounts of sugar-sweetened drinks are more likely to be overweight or obese than those who consume low amounts.

Evidence also suggests that people who consume higher amounts of sugar have more dental caries (cavities).