January 23, 2018

expert reaction to study looking at tax on sugary drinks and alcohol sales

In an economic analysis of sales data, published in the Journal of Epidemiology & Community Health, researchers report that increasing the price of soft drinks may change purchase patterns for alcohol.

Dr John Holmes, Reader in Alcohol Policy, Sheffield Alcohol Research Group, ScHARR, University of Sheffield, said:

“This paper suggests that increasing the prices of sugar sweetened beverages may impact on the sales of alcoholic drinks.  This is a reasonable conclusion, however; the precise impact is difficult to understand as sales of some types of alcoholic drink are estimated to go up while sales of other types are estimated to go down.  Moreover, an increase in the price of medium sugar beverages appears to have the opposite patterns of effects to an increase in the price of low or high sugar beverages.

“There is insufficient information available at this point to judge what the overall effect on alcohol consumption would be (although the appendix may clarify this when it becomes available).  A useful addition to the paper would be to combine the effects on different types of alcoholic drinks to give an overall estimate of the change in alcohol consumption.  Ideally, this would be given in units or grams of alcohol.

“With the information available at this point, the headline of the press release might instead read: Sugar tax on soft drinks might affect alcohol consumption.”

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

“This paper on soft drinks taxes makes many assumptions and whilst it is correct to say costing of other drinks may change, it cannot predict what will happen in reality.  Doing nothing is not an option.  One has to make a change and then examine consequences, whether good or bad and learn from this – this is the basis of science and research and continuous improvements in health.  Of course, as minimal alcohol pricing comes into play in Scotland, the effects north of the border on alcohol consumption may be irrelevant.”

Catherine Collins, Registered Dietitian, said:

“Just because you can, doesn’t mean you should’ comes to my dietitians’ mind with this research that predicts a potential increase in alcohol consumption with a price increase of sugar-sweetened beverages (SSBs).

“This prediction is modelled on Kantar WorldPanel information collected between 2012-13 from almost 32,000 UK households – but only for ‘drink purchases brought into the home’.  It didn’t include your tea money contributions at work, coffeeshop purchases on the way to work, or drinks after work or when eating out.  All of which influence the contribution of different drinks (also calories and sugar) to your overall diet.

“Can 5-year-old data still be relevant to predict future purchasing habits?  That’s impossible to determine, but as a dietitian I’d predict it’s of little relevance to current lifestyle.  Over the last five years the demonisation of fruit juice, variability in alcohol pricing and multipack sizings, online shopping and even our ‘coffeepod culture’ of brewing Barista-style coffee at home all diminish its ability to model predictions for current lifestyle and purchasing habits.

“Kantar World Panel data expressed beverage purchases as a percentage of income.  This is important as it can be easily misinterpreted as ‘lower income families consume more SSBs than higher income families’.  This may well be true from other forms of research, such as the National Diet and Nutrition Survey (NDNS) – but it isn’t useful to model the Kantar data in this way.

“Firstly, identical SSB consumption would represent a smaller ‘percentage spend’ for richer households simply because their disposable income was greater – not necessarily because they bought less.  For example, low income families spent 0.17% of their £24.60 monthly expenditure on sugary drinks, compared to 0.12% of the £36 disposable income in the more affluent families – that appears to be 50% more than higher income families, but converts to £4.18 versus £4.32.  What does that 14p monthly difference mean in relation to the sugar tax?

“Secondly, the data shouldn’t be used to ‘translate’ spending into a ‘volume consumed/ calories contributed to your diet’ approach.  For example, if those same families spent £3 a month on sugary lemonade, did that represent three 2 litre bottles of a premium lemonade brand – or six 2 litre bottles of a cheaper supermarket brand?  Reducing expenditure to buy cheaper own-brand rather than the premium expensive brand doesn’t change intakes of sugary lemonade – just the amount spent on it.  So a spending reduction can’t be used to say ‘people bought less’.  That may be true, but it may also be true that they became more careful shoppers.

“This modelling exercise excludes NDNS robust knowledge that the highest consumers of SSBs are teens and young adults.  If this modelling accurately represented potential changes then younger adults would need to develop skills to circumvent the current Proof of Age demanded at point of sale for alcohol.  It also can’t explain why each of us choose beverages as we do.  Is our gin and diet tonic related to relative taxes on sugary drinks – or because we’re trying to keep our weight in check and a G&dietT is a lower calorie option than a large glass of wine or a pint of cider, which we equally enjoy but at this moment weight loss aims influence our choice?

“Each of us have our own reasons and preferences that influence purchasing behaviour for food and drinks – and how we choose to consume them.  Whether a drink has 8g sugar/100ml (‘medium sugar drink’) or 9g sugar/100ml (‘high sugar drink’) is nutritionally irrelevant – unless you consider a 20kcal difference per pint is important.  This is an academic exercise which professionally I think will be of limited application and little relevance to real life experiences.”

* ‘Effect of increasing the price of sugar-sweetened beverages on alcoholic beverage purchases: an economic analysis of sales data’ by Diana Quirmbach et al. will be published in the Journal of Epidemiology & Community Health on Tuesday 23 January 2018.

Declared interests

Dr John Holmes: “I have received funding from various government bodies, research councils and public health charities for research related to alcohol pricing policies.”

Prof. Naveed Sattar: “No COIs.”

Catherine Collins: “No conflicts of interest.”