Estimated changes in free sugar consumption one year after the UK Soft drinks industry levy came into force: controlled interrupted time series analysis of the National Diet and Nutrition Survey (2011-2019)
Authors: Rogers Nina T , Cummins Steven , Jones Catrin P , Mytton Oliver , Rayner Mike , Rutter Harry , White Martin , Adams Jean 
Published: June 2023

Background

The UK soft drinks industry levy (SDIL) was announced in March 2016 and implemented in April 2018, encouraging manufacturers to reduce the sugar content of soft drinks. This is the first study to investigate changes in individual-level consumption of free sugars in relation to the SDIL.

Methods

We used controlled interrupted time series (2011-2019) to explore changes in consumption of free sugars in the whole diet and from soft drinks alone, 11 months post-SDIL implementation in a nationally representative sample of adults (>18y;n=7,999) and children (1.5-19y;n=7656) drawn from the UK National Diet and Nutrition Survey. Estimates were based on differences between observed data and a counterfactual scenario of no SDIL announcement/implementation. Models included protein consumption (control) and accounted for autocorrelation.

Results

Accounting for trends prior to the SDIL announcement there were absolute reductions in daily consumption of free sugars from the whole diet in children and adults of 4.8g(95%CI: 0.6g to 9.1g) and 10.9g(95%CI: 7.8g to 13.9g), respectively. Comparable reductions in free sugar consumption from drinks alone were 3.0g(95%CI: 0.1g to 5.8g) and 5.5g(95%CI: 2.7g to 8.3g). The percentage of total dietary energy from free sugars declined over the study period but wasn’t significantly different to the counterfactual.

Conclusion

The SDIL led to significant reductions in dietary free sugar consumption in children and adults. Energy from free sugar as a percentage of total energy did not change relative to the counterfactual which could be due to simultaneous reductions in total energy intake associated with reductions in dietary free sugar.

WHAT IS ALREADY KNOWN ON THIS TOPIC

High intakes of free sugars are associated with a range of non-communicable diseases. Sugar sweetened beverages constitute a major source of dietary free sugars in children and adults.

The UK Soft Drink Industry levy (SDIL) led to a reduction in the sugar content in many sugar sweetened beverages; and a reduction in household purchasing of sugar from drinks.

No previous study has examined impacts of the SDIL on total dietary consumption of free sugars at the individual level

WHAT THIS STUDY ADDS

There were declining trends in intake of dietary free sugar in adults and children prior to the UK SDIL

Accounting for prior trends, one year after the UK SDIL came into force, children and adults further reduced their free sugar intake from food and drink by ∼5g and 11g/day, respectively. Children and adults reduced their daily free sugar intake from soft drinks alone by ∼3g and ∼6g/day, respectively.

Energy intake from free sugars as a proportion of total energy consumed did not change significantly following the UK SDIL, indicating energy intake from free sugar was reducing simultaneously with overall total energy intake.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

The UK SDIL was associated with significant reductions in consumption of free sugars from soft drinks and across the whole diet and reinforces previous research indicating a reduction in purchasing. This evidence should be used to inform policy when extending or considering other sugar reduction strategies.

Energy intake from free sugars has been falling but levels remain higher than the 5% recommendation set by the World Health Organization. Reductions in dietary sugar in relation to the SDIL may have driven significant reductions in overall energy.