UK sugar tax reduces daily sugar intake in children and adults, study finds

BMJ GroupJul 9 2024

Daily sugar intake fell by around 5 g in children and by around 11 g in adults in the 12 months following the introduction of the UK's 'sugar tax', formally known as the Soft Drinks Industry Levy, finds an analysis of 11 years of survey data, published online in the Journal of Epidemiology & Community Health.

The sugar from soft drinks alone made up over half this total, the estimates suggest. But overall daily energy intake from free sugars levels are still higher than the updated recommendation from the World Health Organisation (WHO) of 5%---equivalent to 30 g/day for adults, 24 g for 7–10 year olds, and 19 g for 4–6 year olds-; point out the researchers.

Mounting evidence implicates consumption of sugar-sweetened drinks, which are a major source of dietary free sugars, particularly among children, in a heightened risk of weight gain, type 2 diabetes, coronary heart disease and premature death. 

To date, more than 50 countries have introduced a sugar tax on soft drinks in a bid to persuade manufacturers to reformulate their products. The UK did so in 2018.

While the evidence suggests that sugar intake derived from these drinks fell in the year following its introduction, it's not clear whether other sources of dietary sugar were substituted instead.

To assess the impact of the levy on total sugar intake, the researchers drew on 11 years of responses (2008–19) to the annual nationally representative UK National Diet and Nutrition Survey. This captures information on food consumption, nutrition, and nutrient intake in and outside of the home from 500 adults and 500 children over a 4-day period.

The researchers looked particularly at absolute and relative changes in total intake of dietary free sugars from all food and soft drinks combined and from soft drinks alone, to include full and low-calorie soft drinks; semi-skimmed, whole and skimmed milk; fruit juice; and other milk drinks and cream.

Protein intake was used as a comparator because although not subject to a levy, it could still be affected by influential factors such as increases in food prices, say the researchers.

The results draw on information for 7999 adults and 7656 children, and estimated changes in free sugar consumption are based on the period January to March 2019 and compared with what would be expected had no sugar tax been announced and implemented. 

In the period after the sugar tax was announced in 2016, free sugars consumed from all soft drinks more or less halved in children and fell by a third in adults compared with the period before the announcement. 

Taking into consideration previous trends in free sugar consumption, the survey responses indicated that 1 year after the UK sugar tax had come into force children further reduced their free sugar intake from food and drink combined by around 5 g/day (relative reduction of 10%) and adults by around 11 g/day (relative reduction of 20%). 

Over half of this total was from soft drinks alone, accounting for around 3 g/day (relative reduction of 23.5%) in children and around 5 g/ day (relative reduction of just under 40.5%) in adults. Protein intake remained stable throughout in children and adults.

"In children, a daily reduction of 4.8 g sugar equates to approximately 19.2 kilocalories out of an approximate daily intake of 2000 kilocalories which is equivalent to approximately 1% reduction in energy intake," point out the researchers.

Energy intake from free sugars as a proportion of total energy consumed didn't change significantly following the the introduction of the levy, indicating energy intake from free sugar was reducing at the same time as overall total energy intake, and suggesting that people didn't change their diets substantially by substituting more sugary foods and drinks, say the researchers.

It wasn't possible to study different age groups due to the limited number of participants, but falls in the levels of sugar in food and drink may have affected different age groups differently, say the researchers.

For example, the largest single contributor to free sugars in 4–10 year olds is cereal and cereal products, followed by soft drinks and fruit juice. By the age of 11–18, soft drinks provide the largest single source (29%). For adults the largest source of free sugars is sugar, preserves, and confectionery, followed by non-alcoholic drinks, they explain.

The fall in consumption of free sugars observed in the whole diet rather than just from soft drinks suggests that consumption of free sugar from food was also falling from as early as 2008, they add. This might be because of the public health signaling following the announcement, they suggest.