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Professor Susan Jebb, who leads the CLAHRC’s ‘Behaviour Change: Diet and obesity’ research theme, is co-author of new research, published in The Lancet Public Health, estimating the health benefits of the UK soft drinks industry levy.

What might the soft drinks industry do when the UK begins to tax sugary drinks in April 2018, and how might this impact on the health of the UK?

These are the questions asked in a new paper published today in The Lancet Public Health.

The UK soft drinks levy, often called the ‘sugar tax’, proposes to add a high tax to drinks with more than 8g of sugar per 100 mL, a lower tax on drinks with 5-8g of sugar and no tax on drinks with less than 5g or with no sugar.

The levy was developed in response to concerns about the high levels of sugar in many soft drinks, which have no other nutritional value, and the effect they may be having on people’s health, especially a potential link to increasing rates of obesity. For example, the 39g of sugar in a single 330mL can of a popular fizzy soft drink easily exceeds the recommended daily sugar intake for a five-year-old (19g).

It is hoped that the increased cost of high-sugar drinks over low or zero sugar alternatives will encourage manufacturers to reformulate their leading brands with less sugar, as well as making consumer purchase fewer of them, instead opting for cheaper low-sugar alternatives.

In the new research, which was not carried out as part of CLAHRC Oxford, the researchers from the University of Oxford and the University of Reading explored different ways in which the soft drinks industry might respond to the tax and how this might affect public health.

They examined three possible scenarios:

  1. Reformulating drinks to reduce their sugar content.
  2. Increasing the product price.
  3. Changing the market share of high, mid-, and low-sugar drinks, through re-focussed advertising on lower sugar products, for example.

For each scenario, they included a best and worst case. For example, for scenario 1, the researchers ‘best case’ was looking at what would happen if manufacturers reformulated high and mid-sugar drinks to use 30% and 15% less sugar, while the ‘worst case’ was a 5% reduction across both types.

The researchers then assessed and compared the possible impact of each scenario on the risks of dental caries (tooth decay or cavities), type 2 diabetes, and obesity was then compared.

Overall, the study found that an industry response that focuses on reducing sugar content (scenario 1) is likely to have the greatest impact on health, with additional benefits if industry increases the price of high and mid-sugar drinks, or can successfully use marketing to persuade consumers to switch to low sugar drinks.

The authors estimate that a reduction of 30% in the sugar content of all high-sugar drinks – a step already implemented by some manufacturers – and a 15% reduction in mid-sugar drinks could result in 144,000 fewer adults and children with obesity, 19,000 fewer cases of type 2 diabetes per year, and 270,000 fewer teeth suffering from decay annually.

Children are likely to benefit most, however, the study also shows that the health benefits of the tax could be reduced if the industry responds by increasing the price across their drinks range, rather than just those with more than 5g of sugar per 100ml.

Prof Susan Jebb said, “In spite of the uncertainties, the direction of the effect is clear; this levy will have a positive impact, especially on children’s health. Of course, on its own, a soft drinks levy cannot solve the obesity crisis, but we should not underestimate the importance of this step, both for the UK and as a case study for other parts of the world. Then, once this Bill is passed, we need to consider how to take effective action to reduce other sources of sugar in children’s diets, notably confectionery, which has been relatively overlooked while hearts and minds have been focused on the soft drink levy.”

A health impact assessment of the UK soft drinks industry levy: a comparative risk assessment modelling study. Briggs ADM, Mytton OT, Kehlbacher A, Tiffin R, Elhussein A, Rayner M, Jebb SA, Blakely T, Scarborough P. The Lancet Public Health, 2016;

Read about CLAHRC Oxford's diet and obesity-themed research here.