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Overall and income specific effect on prevalence of overweight and obesity of 20% sugar sweetened drink tax in UK: econometric and comparative risk assessment modelling study

BMJ 2013; 347 doi: (Published 31 October 2013) Cite this as: BMJ 2013;347:f6189
  1. Adam D M Briggs, academic clinical fellow1,
  2. Oliver T Mytton, academic clinical fellow12,
  3. Ariane Kehlbacher, lecturer3,
  4. Richard Tiffin, director3,
  5. Mike Rayner, director1,
  6. Peter Scarborough, senior researcher1
  1. 1British Heart Foundation Health Promotion Research Group, Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, UK
  2. 2UK Health Forum, Victoria House, Southampton Row, London WC1B 4AD, UK
  3. 3Centre for Food Security, University of Reading, PO Box 237, Whiteknights, Reading RG6 6AR, UK
  1. Correspondence to: M Rayner mike.rayner{at}
  • Accepted 3 September 2013


Objective To model the overall and income specific effect of a 20% tax on sugar sweetened drinks on the prevalence of overweight and obesity in the UK.

Design Econometric and comparative risk assessment modelling study.

Setting United Kingdom.

Population Adults aged 16 and over.

Intervention A 20% tax on sugar sweetened drinks.

Main outcome measures The primary outcomes were the overall and income specific changes in the number and percentage of overweight (body mass index ≥25) and obese (≥30) adults in the UK following the implementation of the tax. Secondary outcomes were the effect by age group (16-29, 30-49, and ≥50 years) and by UK constituent country. The revenue generated from the tax and the income specific changes in weekly expenditure on drinks were also estimated.

Results A 20% tax on sugar sweetened drinks was estimated to reduce the number of obese adults in the UK by 1.3% (95% credible interval 0.8% to 1.7%) or 180 000 (110 000 to 247 000) people and the number who are overweight by 0.9% (0.6% to 1.1%) or 285 000 (201 000 to 364 000) people. The predicted reductions in prevalence of obesity for income thirds 1 (lowest income), 2, and 3 (highest income) were 1.3% (0.3% to 2.0%), 0.9% (0.1% to 1.6%), and 2.1% (1.3% to 2.9%). The effect on obesity declined with age. Predicted annual revenue was £276m (£272m to £279m), with estimated increases in total expenditure on drinks for income thirds 1, 2, and 3 of 2.1% (1.4% to 3.0%), 1.7% (1.2% to 2.2%), and 0.8% (0.4% to 1.2%).

Conclusions A 20% tax on sugar sweetened drinks would lead to a reduction in the prevalence of obesity in the UK of 1.3% (around 180 000 people). The greatest effects may occur in young people, with no significant differences between income groups. Both effects warrant further exploration. Taxation of sugar sweetened drinks is a promising population measure to target population obesity, particularly among younger adults.


  • Contributors: ADMB and OTM contributed equally to this manuscript. ADMB, OTM, MR, and PS devised the study. AK and RT provided advice on and undertook the econometric modelling. PS developed the PRIME model and provided specific guidance on modelling. ADMB and OTM did the health modelling and drafted the manuscript. All authors contributed to the study design and reviewed and critiqued the final manuscript. ADMB and OTM are the guarantors.

  • Funding: No explicit funding for this work was sought. MR and PS are funded by the British Heart Foundation. ADMB and OTM are National Institute for Health Research funded academic clinical fellows in public health.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available from the corresponding author) and declare: no support from any organisation for the submitted work; RT and AK have received research grants from the Union of European Soft Drinks Association; MR and PS have received research grants from the British Heart Foundation; MR is chair of Sustain.

  • Ethical approval: This study used routinely collected publicly available datasets. As such, ethics approval was not required.

  • Data sharing: No additional data available.

  • Declaration of transparency: The lead authors (the manuscript’s guarantors) affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

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