Sugary drink interventions – what works? – Expert Reaction

Researchers are trialling lots of different ways to influence us to buy or drink fewer sugary drinks – but what actually works? The latest Cochrane Review evaluates several different interventions. 

The review authors identified a number of measures which the available scientific evidence indicates reduces the amount of sugary drinks people drink. These measures included:

  • Labels that are easy to understand, such as ‘traffic-light’ labels, and labels that rate the healthiness of beverages with stars or numbers.
  • Limits to the availability of sugary drinks in schools.
  • Price increases on sugary drinks in restaurants, stores and leisure centres.
  • Children’s menus in chain restaurants which include healthier beverages instead of sugary drinks as the default.
  • Promotion and better placement of healthier beverages in supermarkets.
  • Government food benefits (e.g. food stamps) which cannot be used to purchase sugary drinks.
  • Community campaigns focused on supporting healthy beverage choices.
  • Measures that improve the availability of low-calorie beverages at home, e.g. through home deliveries of bottled water and diet beverages.

Cochrane reviews are more comprehensive than most research reviews as they also rate the quality of evidence. Most of the evidence they found was Low-Moderate grade (Cochrane grades evidence as either: Very Low, Low, Moderate or High), with none of the interventions the analysed rating as high grade evidence.

Note: The reviewers specifically didn’t look into sugar taxes as they plan to evaluate them separately, with another report coming late 2019.

The SMC asked experts to comment on the Cochrane Review, feel free to use these in your reporting. 

Dr Eric Crampton, Chief Economist, The New Zealand Initiative, comments:

“The Cochrane Review provides an important synthesis of the evidence regarding non-tax interventions aimed at reducing consumption of sugar-sweetened beverages [SSBs].

“The review found that many often-recommended measures have little evidentiary base, with certainty of evidence rated as very low. Interventions in this category included measures like healthier vending machines in workplaces and schools, restrictions on the number of stores selling sugar-sweetened beverages, urban planning restrictions on new fast-food outlets, and menu-board calorie labelling. No studies were found that might provide basis for restrictions on advertising.

“Some measures showed promise, with a moderate certainty of evidence established across numerous studies.

“Improved access to low-calorie beverages in the home environment reduced SSB consumption, but many included studies focused on places without reliable access to clean drinking water. Regular home delivery of free non-SSB drinks across broad swathes of the population seems unlikely to pass any reasonable cost-benefit assessment, and especially in places where piped water is of reasonable quality.”

“Restrictions placed on purchases funded through food benefit programmes reduced sugar-sweetened beverage consumption, and could be implemented in New Zealand by adding sugar-sweetened beverages to the list of prohibited purchases on Work and Income Payment Cards. But the administrative costs may not be trivial, and the imposition on low-income households who enjoy soda occasionally should not be ignored.

“Small prizes for selecting healthier beverages in primary school cafeterias showed some promise.

“While price increases in individual targeted stores showed reduced sales of sugar-sweetened beverages in those particular venues, the surveyed studies in that area do not look at overall consumption; people could easily have shifted to purchasing from outlets where prices had not been hiked.

“And while the review authors tentatively suggested a somewhat broader set of interventions may prove effective, they also warned that their confidence in the likely effects is low to moderate. Rather than providing evidence for policy change, we should view the report as suggesting measures potentially worth trialling within an appropriate experimental framework designed to improve the evidence base.

“Where the evidence base presented for any substantial effect of interventions is moderate at best, even without being evaluated as part of a broader cost-benefit assessment that weighs implementation costs and costs to consumers, we should be highly sceptical of any calls for strong intervention based on this report. It should rather temper our enthusiasm for large-scale measures likely to impose substantial cost for rather less certain benefit. Pilot studies and trials of some of the more promising interventions may be warranted.”

Conflict of interest statement: The New Zealand Initiative is an independent think-tank funded by the membership subscriptions of many of New Zealand’s most prominent companies, including supermarkets and food industry companies. The breadth of the Initiative’s membership base across a wide range of industries helps ensure its independence.

Dr Bodo Lang, Head of Marketing at The University of Auckland, comments:

“Global obesity rates and related illnesses are increasing at an alarming rate. The resulting health costs at the societal level and the negative impact on individual lives is enormous. Sugary drinks have been shown to contribute towards this health crisis.

“Therefore, having scientific evidence that assesses the effectiveness of different interventions is of paramount importance. The results of the study are highly useful for a variety of organisations but most importantly for central and local governments who can affect systemic change in today’s complex food environments.

“What makes the findings of this study particularly useful is the fact that it is based on multiple other studies, thereby avoiding the biases and limitations of any single study.

“Importantly, the study indicates that a number of interventions are effective across different cultures and geographic regions. This indicates the universal impact that these interventions appear to have on consumers’ consumption of sugary drinks.

“What makes the study particularly important is the fact that consumption of sugary drinks in many markets is at an all-time high. Specifically, many markets show a decline in consumption of traditional soft drinks (e.g. colas or sodas) but this decline has been more than compensated for by the rapid increase in consumption of flavoured milks, sports drinks, energy drinks and other types of beverages. Therefore, the need to reduce the consumption of sugary beverages is now greater than ever.”

No conflict of interest.

Associate Professor Pawel Olszewski, Physiology lecturer, University of Waikato, comments:

“Based on the findings, I would emphasise that the evidence that supports the effectiveness of environmental interventions to lower sugary drink consumption is of low-to-moderate certainty. Long-term effects of these interventions and their suitability for large-scale implementation are yet to be determined.”

No conflict of interest.

Our colleagues at the UK SMC also asked experts to comment. 

Dr James Doidge, Senior Research Associate, UCL, said:

“Cochrane reviews provide some of the most valuable, fair and transparent summaries of the available evidence on many health interventions.  While this review provides useful insights into environmental measures that could be implemented to reduce consumption of sugary drinks, one really interesting question is how these measures stack up against the taxes that are currently being implemented or considered by many governments.  Unfortunately, taxation measures are to be covered by a separate review.  Nor does this review compare the effectiveness of methods targeting consumption of sugary drinks with other ways of tackling obesity, for which sugary drinks are only part of the story.

“One thing the review does highlight is the paucity of research in this area, with available studies constituting only ‘low’ or ‘moderate’ certainty of evidence.  From this, the authors rightly conclude that further implementation of interventions should be accompanied by further evaluation of their effectiveness.”

No conflict of interest.

Prof Naveed Sattar, Professor of Metabolic Medicine, University of Glasgow, said:

“This is a substantial and well considered body of work on a topic that is important and non-controversial as there is little need to consume sugar sweetened beverages in the modern day of abundant calorie-rich temptations in many forms.  Whilst the evidence base is not complete for all key suggestions to reduce consumption of sugary drinks, it is sufficiently strong to move ahead and push governments and other agencies to implement as many as possible and then monitor the changes.  The public has little to lose from these changes and much to gain.  Most people’s palates can be retrained to enjoy low calories drinks or water and so lessening the availability of sugar rich drinks makes complete sense.”

No conflict of interest.