Sugar levels in UK soft drinks lowered following government levy

The research was carried out by teams at the University of Exeter, working with University of Oxford, University of Cambridge, London School of Hygiene and Tropical Medicine, Warwick and Bath Universities and is funded by the National Institute for Health Research (NIHR).

The SDIL applies to drinks containing more than 5g of sugar per 100ml, but not to fruit juice, milk-based drinks, alcoholic drinks, or drinks from companies with sales of less than 1million litres per year. The changes in drink formulation brought about by the SDIL have been much greater than achieved by voluntary industry initiatives. The researchers found that very few eligible drinks, just 15 per cent, were still liable for the levy by February 2019. Prior to the announcement of the levy, 52 per cent of eligible drinks were liable for the tax.

Dr Peter Scarborough, associate professor at the Nuffield Department of Population Health at the University of Oxford, led the analysis, which is the first direct evaluation of the effects of the SDIL on drink formulation and has been published in PLoS Medicine. Sugary drinks taxes are a key measure recommended by the World Health Organization to tackle the problem of obesity and related health conditions, and Dr Scarborough says that their new analysis shows that such fiscal interventions can be a useful and effective tool for improving the population’s diet.

‘It is vital that public health interventions are evaluated using robust methods so that we can discover what is effective at preventing ill health. The levy is an important policy as it both reduces the sugar level of many drinks and increases the prices of high sugar drinks, helping the public to make healthier choices. These population approaches are important not only for preventing disease but also for reducing health inequalities,’ said Dr Scarborough.

Professor Richard Smith, of the University of Exeter, was part of the evaluation team. He said: “This is the first robust evidence to demonstrate that the SDIL is achieving its stated aim to reduce sugar content through incentivising reformulation of drinks by manufacturers.  We must remember though that many drinks, such as milk-based, are exempt and we have seen an increase in the range of beverages available to consumers.  Another area of the project is looking at this wider context and possible substitution effects, but these first major results from the study are very promising in indicating that there has been a positive impact on reducing overall sugar consumption.”

He added that “it is also important that such a fiscal incentive appears to have been more effective than other non-fiscal interventions that have been advocated, such as food labelling or information campaigns, and extension of fiscal measures to other beverage or foods high in sugar could be a fruitful area to examine.  However, it’s likely that ultimately a combination of various fiscal and non-fiscal measures will be the most effective.”

The researchers assessed a dataset of soft drinks available in UK supermarkets from September 2015-February 2019. Prior to the announcement of the SDIL, there was already a slight downward trend in the sugar content of drinks. Dr Scarborough and the team compared the sugar content of drinks to that background trend, as a measure of how much the SDIL had affected drinks formulation.

After the announcement of the SDIL, the percentage of drinks liable for the levy began to reduce faster than the background trend. For example, if the trend had continued, by February 2019, 49% of drinks would still have been eligible for the tax, rather than the 15% actually seen. The biggest changes in drink formulation happened just before the implementation of the levy. In the 100 days either side of the implementation date (6 April 2018), 11% of the eligible drinks changed sugar content so that they were not liable.

Supermarkets had been reducing the sugar content of their own brand drinks before the SDIL was announced, so the changes were less dramatic than for branded drinks when assessed separately.

Price analysis showed that, for branded drinks, around half of the levy was passed onto consumers in higher prices of drinks in the higher levy category after the introduction of the SDIL, while lower levy drinks reduced in price.

Professor Martin White of the MRC Epidemiology Unit at the University of Cambridge, Chief Investigator for the SDIL evaluation, said: ‘These are the first results from our independent evaluation of the Soft Drinks Industry Levy and focus on the reformulation efforts of soft drinks companies. The findings suggest that the levy has been effective in prompting industry reformulation to reduce sugar content of many soft drinks. However, the marketing strategies of soft drinks manufacturers compared to supermarkets vary considerably, with differences in sugar content, sizes and prices of drinks as a result of the levy. Further research is looking at how these changes affect purchases and consumption of soft drinks and potential health impacts among the public, as well as impacts on businesses and the economy. These will be reported over the next year as they become available.’