The introduction of taxes on soft drinks high in sugar has been found to be an effective way to make manufacturers reformulate their products, which has led to a reduction in sugar consumption, according to a study published in the BMJ


The SDIL, unveiled in the budget of March 2016 by the then chancellor George Osborne and enacted in April 2018, applies a tier tax on soft drinks with 5 or more grams of sugar per 100 millilitres. The levy increased the price of high-sugar soft drinks in an effort to reduce sales of these products, but also aimed to get manufacturers to reformulate their products to reduce their sugar content. And the study published in the BMJ found that within a year of the SDIL introduction this is exactly what happened; to avoid price hikes, the drinks industry reformulated their products to reduce the sugar content.


The study in the BMJ found that one year after the implementation of the SDIL, sugar purchased as part of soft drinks to be consumed at home fell by 30g per household per week. There was, however, no significant change in the volume of drink purchased. This meant that consumers drank less sugar, but the industry’s bottom line was unaffected.


Prior to the SDIL introduction, researchers had modelled its likely effect on sugar consumption and considered that the tax could be expected to lead to a decrease in sugar consumption from these drinks in the range 7-38 g per person per week, which would be associated with a reduction in the number of obese individuals in the UK of 0.2-0.9%. The reduction in sugar consumption of 30g per person per week found in the real-life study was in the range predicted. 


The excess consumption of free sugar is known to be a major contributor to diet related diseases, including tooth decay, type 2 diabetes, obesity, and cardiovascular disease. Now, however, there is also strong evidence that mortality from Covid-19 disease is far higher in people who are obese. A recent report from the World Obesity Federation found that Covid-19 death rates are 10 times higher in countries where more than half of the adult population is classified as overweight.


As the free sugar in soft drinks has no nutritional benefit whatsoever, soft drinks have long been considered a perfect target for public health action of this kind. But it is also possible to introduce some type of levy on other food groups high in sugar, fat and salt.


Such a levy was recommended back in 2015 in a report from Public Health England (PHE), called Sugar Reduction: the Evidence for Action, which set out a range of tough policies that it said needed to be implemented to reduce the consumption of sugary foods and drinks fuelling the obesity crisis. 


Its recommendations were almost completely ignored by the Conservative government then led by David Cameron. The Guardian at the time reported that Cameron did not even read the report before dismissing the idea of a tax on sugary foods.


The report recommended the introduction of a price increase of a minimum of 10%-20% on high-sugar products through the use of a tax or levy such as on full-sugar soft drinks. The only action from this report that made it into law was the SDIL; reformulation of foods to reduce sugar, fat and salt in other food groups was encouraged but was entirely voluntary.


The findings from the study on the SDIL are important for two reasons: it shows the success of a mandatory approach, which targets the profits of the manufacturers, but also shows that such approaches do not inevitably lead to a reduction in sales and therefore profits for the manufacturers.


An editorial in the BMJ notes that it is unsurprising that “embedding profit motives in regulation is an effective way to shift the behaviour of profit driven enterprises.” The SDIL has brought about “widespread reformulation with potential benefits to population health, even without reliance on consumer behaviour change.” 


There was strong lobbying against the SDIL at the time by industry bodies, including the Food and Drink Federation, and individual companies. They thought that the levy would have little effect on consumer behaviour and have no impact on obesity.


Looking at the study it appears that consumer behaviour has not in fact changed, volumes remain the same, but the SDIL has forced manufacturers to actually reformulate their products leading to a positive public health outcome.


In contrast, Public Health England’s attempts to get food companies to cut salt and sugar in other products voluntarily have largely failed.


The government’s sugar reduction programme, a voluntary scheme for manufacturers introduced in 2015, aimed for a 20% reduction in sugar by 2020 for eight categories of foods, including breakfast cereals, yoghurts, puddings, biscuits, and cakes. The latest available assessment of the period 2015 to 2018 found that the overall reduction in sugar per 100g was just 2.9% by 2018; it was highly unlikely that it would reach its target of 20% by 2020. There were also considerable differences between food categories – yoghurt/fromage frais were down 10.3% and breakfast cereals down 8.5%, but sugar in puddings and sweet confectionery was actually up 0.5% and 0.6%, respectively.


Looking at the poor performance of the voluntary approach, the success of the mandatory SDIL, which was known before the publication of the paper in the BMJ,  and the new information on the effect of obesity on mortality in Covid-19 disease, it was concerning and surprising that the UK government’s new obesity strategy unveiled in July 2020 (see box) contained no plans for a similar levy for foods high in sugar, fat and salt. Indeed, with the exception of the ban on TV and online adverts for high fat, sugar and salt food before 9pm and some restrictions on food promotions, the strategy, together with the related Better Health strategy, relies heavily on individuals making choices and taking responsibility. Manufacturers appear to have been given a free pass.


Indeed, critics (from both sides of the debate – food manufacturers and public health) were quick to point out that the strategy relies on tired outdated ideas.


In an editorial on the obesity strategy in the BMJ, Christina Marriott, chief executive of the Royal Society for Public Health, said: 


“Simply passing the buck to the individual with another healthy eating campaign will not turn the tide on this silent epidemic . . . Unless the government has the courage to stand up to industry where it matters—taxing unhealthy foods and restricting the relentless bombardment of junk food and its advertising—we are concerned that the new plans will be another wasted opportunity.”


An editorial in Nature Reviews Endocrinology noted that the obesity strategy document does not address the complex underlying causes of obesity; the genetic, environmental and socioeconomic factors that are involved. In fact, the strategy perpetuates the message that simply eating less and moving more will solve obesity and the “choice of language could be damaging as it encourages the blaming and shaming of people with overweight and obesity.” 


Faced with overwhelming evidence from the SDIL that industry can rise to the challenge of reformulation if its profits are on the line, it surely makes sense to extend the levy to other food groups high in fat, sugar and salt. Now that the NHS is under such extreme pressure and the link between Covid-19 deaths and obesity is obvious, it seems almost farcical that the government is yet again taking an approach that blames individuals for their poor choices and lack of responsibility, and ignores environmental and socioeconomic factors, whilst completely ignoring an approach, the SDIL, that has been found to be effective.


Obesity strategy recommendations – July 2020

  • Ban on TV and online adverts for food high in fat, sugar and salt before 9pm
  • End of deals like ‘buy one get one free’ on unhealthy food high in salt, sugar and fat
  • Calories to be displayed on menus to help people make healthier choices when eating out – while alcoholic drinks could soon have to list hidden ‘liquid calories’
  • New Better Health campaign to help people lose weight, get active and eat better after COVID-19 ‘wake-up call’


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