High consumption of sugar sweetened beverages (SSBs) is associated with increased risk of tooth decay, obesity, type 2 diabetes and cardiovascular disease. As such, the World Health Organization recommends taxes on these drinks to try to reduce consumption.
The UK soft drinks industry levy (SDIL) is a two tiered tax levied on soft drinks manufacturers from April 2018 to encourage them to reduce the sugar content in their products.
Under the SDIL, drinks with more than 8 g sugar/100 mL (high tier) are taxed at £0.24/L and drinks with more than 5 g but less than 8 g sugar/100 mL (low tier) are taxed at £0.18/L. Drinks with less than 5 g of sugar/100 mL (no levy) are not taxed.
Although previous studies have explored the effect of consumer-facing SSB taxes, none have explored the effect of the implementation of the SDIL on purchases, taking existing trends in purchases into account.
To address this gap, a team of researchers led by University of Cambridge’s MRC Epidemiology Unit decided to examine changes in household purchases of drinks and confectionery before and after implementation of the SDIL.
They studied changes in the volume of, and amount of sugar in, household purchases of drinks in each levy tier, exempt drinks categories (including alcoholic drinks), and confectionery from two years before the announcement of the SDIL to one year after its implementation (March 2014 to March 2019).
Their findings are based on around 31 million purchases by an average of 22,183 households that recorded all food and drink brought into the home (including those ordered online and delivered) on a weekly basis during this period.
Overall, they show that compared with pre-announcement trends, the total volume of all taxed and untaxed soft drinks purchased did not change one year after implementation.
When all taxed and untaxed soft drinks were combined, the volume of drinks purchased did not change, but sugar purchased in these drinks decreased by around 30 g per household per week, or almost 10% – equivalent to three fewer teaspoons, or one 250 mL serving of a drink with 5 g sugar per 100 mL per person per week.
Purchases of confectionery and alcoholic drinks did not change.
The authors acknowledge some study limitations. For example, data only included purchases brought into homes, which could limit the generalisability of the findings. However, they used a large, nationally representative dataset, included a control category, and explored changes in two potential substitute categories – alcohol and confectionery.
As such, they say tiered SSB taxes such as the SDIL “might represent a benefit for public health (by reducing sugar purchased from soft drinks without substitution to confectionery and alcohol) without any commensurate harm to the soft drinks industry (by not affecting total volume of soft drinks purchased).”
The research is published here: Changes in soft drinks purchased by British households associated with the UK soft drinks industry levy: controlled interrupted time series analysis