Celebrity chef Jamie Oliver, who campaigned for the introduction of a sugar tax in the UK, introduced a 10p levy on sugar-sweetened beverages across 37 restaurants in his national chain in September 2015.
The restaurant chain also re-organized its non-alcoholic beverage menu into two sections: SSBs and other beverages (juice, water and diet cola). The SSB menu also included an explanation on why a levy was being introduced; with proceeds going to a Children’s Health Fund.
The introduction of the levy also tied in with Oliver’s Channel 4 TV documentary, ‘Jamie’s Sugar Rush’.
A study, led by the London School of Hygiene & Tropical Medicine with the University of Cambridge and funded by the National Institute for Health Research, has now analyzed the effect of the levy on sales.
Small levy, large effect
After adjusting for general trends in sales, researchers found that the 10p levy, combined with activities such as re-designing menus, offering new lower sugar drinks and related publicity, was associated with an 11% decline in sales of SSBs per customer 12 weeks after the levy was introduced.
A decline in sales of 9.3% per customer was still observed six months after the levy was introduced.
Lead author Steven Cummins, Professor of Population Health at the London School of Hygiene & Tropical Medicine, said: "Our study showed that a combination of the levy, menu changes and clearly explaining to customers why it was introduced and that the proceeds would go directly to a worthy cause, looks to have had a relatively large effect on consumer behavior given the small size of the levy.
“This type of 'complex intervention' has also been shown to be successful in economic studies of levies on alcohol."
Effect on wider beverage sales
The study also found there was a general decrease in the number of non-alcoholic beverages sold per customer, with the exception of fruit juice, which increased by 22% after six months. Sales of diet cola and bottled waters also declined.
"A possible reason for this decline could be that more people were choosing tap water, but data on tap water orders was not available as it was not recorded on the restaurant's sales system,” added Cummins.
UK sugar tax
The UK will introduce its soft drinks industry levy in April 2018. The levy rate for added sugar drinks with a total sugar content of 5g or more per 100ml will be set at 18 pence per liter; and those with 8g or more per 100ml will be set at 24 pence per liter.
“Overall, our study suggests that a small levy on sugar-sweetened drinks sold in restaurants, coupled with complementary activities, may have the potential to change consumer behavior and reduce the consumption of these drinks which are associated with major health risks."
The authors add the study raises interesting questions as to how fiscal interventions may work beyond the price increase: in this case, how big a factor the menu change and explanation of the levy was in influencing consumers’ choices.
The authors acknowledge the study only considered one chain of restaurants; and says further research with a longer follow-up period would be required to assess whether the drop in sugary drink consumption was sustained.
Study: Change in non-alcoholic beverage sales following a 10-pence levy on sugar-sweetened beverages within a national chain of restaurants in the UK: interrupted time series analysis of a natural experiment
Authors: Cornelsen L, Mytton OT, Adams J, et al
J Epidemiol Community Health 2017;71:1107-1112. November 2017.