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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: https://doi.org/10.1136/bmj.f6189 (Published 31 October 2013) Cite this as: BMJ 2013;347:f6189

Re: 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

It is a positive development that public health specialists are now working actively on price instruments as part of obesity policy. This is the sixth high-profile proposal in the UK in the past 18 months for taxes on “bad” foods. It is the most ambitious to date, extending the analysis beyond the consequences for consumption to estimating the effects on obesity.

However, none of the other five have been adopted or even seriously discussed in policy-making circles. The suggestion here, for a 20% tax on soft drinks, is also unlikely to be implemented and would not make much difference if it were. The reasons are economic ineffectiveness and political unacceptability.

The authors are admirably clear about their methods. But, at the end of the day, this is yet another modelling exercise reworking poor primary data. Nonetheless, it confirms the stark conclusions of earlier studies --– the benefits are tiny.

The best they can claim is that 20% tax would reduce consumption by 4kcal per person per day. That is one gram of sugar. There are 35g in a single, standard, small can of cola.

As for health effects, the tax would cut the number of the overweight and obese by less than 1%. Put that in context: roughly 60% of British adults weigh too much.

Such meagre benefits are part of the reason why all tax proposals have foundered. Following the March 2012 budget, a popular revolt swelled against plans for a “pasty tax”. In a unique U-turn, the government backed down.

After that experience, no rational British politician would risk antagonising voters by supporting an even higher tax on an even more popular product for such negligible gains.

And they are unlikely to be attracted to the proposal in the supporting Editorial by Block – that governments introduce soft drinks taxes on a trial basis so academics can conduct “quasi-experiments” to gather “real world evidence” on whether they work of not. There are less risky ways to raise the price of sugar (1).

Both papers are combinations of methodological sophistication and political naivete. Unlike the model makers, no real world policy makers will find soft drinks taxes “promising”, but rather impotent and improbable.

To date, the new interest in price instruments has concentrated on taxes to raise the prices of “bad” foods. We also need to consider instruments that lower the prices of “good” foods (2) .

But that is another, longer story for a different time and a different place. For the moment, the core conclusion remains unaltered: soft drinks taxes will not work (3).

Winkler J (2010), How to raise the prices of unhealthy foods, BMJ 2010;341:c4177

Winkler J (2012), Make the healthy choice the cheaper choice, BMJ 2012;344:e3834

Winkler J (2012), Why soft drinks taxes will not work, British Journal of Nutrition 2012, 108, 395–396

Competing interests: No competing interests

03 November 2013
Jack T Winkler
Professor of Nutrition Policy
formerly at London Metropolitan University
28 St Paul Street, London N1 7AB