Modelling the potential impact of food taxes based on nutrient and energy content in the UK: a simulation study

Building on the success of the Soft Drinks Industry Levy (SDIL), new tax proposals have been considered in the public health policy debate in the UK. To inform such debate, estimates of the potential impacts of alternative tax scenarios are of critical importance. Using a modelling approach, we studied the effects of two tax scenarios: (1) a hypothetical excise tax designed to tax food products included in the Sugar Reduction Programme (SRP), accounting for pack size to reduce the convenience of purchasing larger quantities at once; (2) an ad valorem tax targeting products based on the UK Nutrient Profile Model (NPM). Simulations of scenario 1 show a reduction in sugar purchased of up to 38 %, with the largest decreases observed for sweet confectionery with a tiered tax, similar in structure to the SDIL. Expected food reformulation in scenario 1 led to further decreases in sugar purchased for all categories. In scenario 2, under the assumption that the tax would not affect purchases of healthier products, a 20 % tax on less healthy products would reduce total sugar purchased by 4·3 % to 14·7 % and total energy by 4·7 % to 14·8 %. Despite some limitations and assumptions, our results suggest that new fiscal policy options hold a significant potential for improving diet quality beyond what has been achieved by the SDIL and SRP. An estimated increase in consumer expenditures in both scenarios suggests that attention needs to be paid to potentially regressive effects in the design of any new food taxes.