In recent times, three significant publications have emerged
which should be taken on board by those involved in the debate on sugar tax.
The first is the very recent (June 2018) report of the World
Health Organisation (WHO) High Level
Commission on Non-Communicable Diseases,
entitled “Time to deliver”[1].
The report highlights the global burden on chronic diseases caused by tobacco,
alcohol and poor nutrition. The report has powerful messages to Governments on
the directions to take in combatting chronic disease and it points out that
investment pays off: “WHO’s global
business case for NCDs showed that low- and lower-middle-income countries put
in place the most cost-effective interventions for NCDs, by 2030, they will see
a return of $ 7 per person for every one dollar invested”. In Ireland,
where the obesity bill alone is €1.2bn, we might eat into that figure with an
investment of about €180m. At present, we spend almost a tiny fraction of that
budget on health promotion against the issues of alcohol, tobacco and
nutrition. The former two actually generate a significant income for the state
through taxation and the Commission’s report very strongly supports such
taxation. However, when it comes to sugar tax, the Commission is somewhat coy: The Commissioners represented rich and
diverse views and perspectives. There was broad agreement in most areas, but
some views were conflicting and could not be resolved. As such, some
recommendations, such as reducing sugar consumption through effective taxation
on sugar-sweetened beverages and the accountability of the private sector,
could not be reflected in this report, despite broad support from many
Commissioners. This conservative language contrasts with the hype of
the advocates of the so-called sugar tax, effectively, a tax on sugar sweetened
soda. Food for thought indeed. And of course the finger is now pointed at the
US with suggestions that it was Eris Hargan, US Deputy Secretary of Health who
was the blocking commissioner[2]. Whether
Hargan did a solo run and is playing to the gallery is anybody’s guess.
The second study is a scientific paper from a group of
British academics who explored whether taxation of sources of sugar other than
sugary sodas[3]. Many of
us have argued, that the global fashion of taxation of sugars via a tax on
sugary sodas, fails to address the real issue of taxing sugars. These authors
looked at a broader approach to sugar taxation: “Policies that lead to increases in the price of chocolate and
confectionery, cakes and biscuits may lead to additional and greater health
gains than similar increases in the price of (sugar sweetened beverages) SSBs
through direct reductions in the purchases of these foods and possible positive
multiplier effects that reduce demand for other products. Although some
uncertainty remains, the associations found in this analysis are sufficiently
robust to suggest that policies, and research, concerning the use of fiscal
measures should consider a broader range of products than is currently the case”.
Now at least we would be forced to take a detailed look at all sources of
sugar and how that varies across age groups. These are our own research data
for the Irish population[4].
|
|
% contribution to Added Sugars
|
||
|
Main food groups involved
|
Children
|
Teenagers
|
Adults
|
|
Table sugar & jams
|
7
|
9
|
23
|
|
Biscuits
|
11
|
8
|
9
|
|
Cakes, buns & pastries
|
5
|
5
|
8
|
|
Carbonated beverages
|
16
|
22
|
12
|
|
Squashes & cordials
|
12
|
5
|
2
|
|
Chocolate confectionery
|
13
|
15
|
10
|
|
Non-chocolate confectionery
|
9
|
7
|
2
|
The complexity grows and in the third of the recent papers,
the complexity of sugar taxes are elegantly illustrated. Quite how the public would respond to a tax on cakes, confectionery etc as opposed to a soda tax is as yet unknown but somehow I get the feeling that it would be way less popular.
And now to the final report and by far the most significant. Three years ago, The New Zealand Ministry of Health commissioned
a report on the benefits or otherwise of the globally popular sugar tax. It
concluded that “there isn’t yet robust
evaluative evidence on whether they are effective, or on the size and
persistence of any impacts”. In late 2017, the same ministry returned to
this issue and commissioned the New Zealand Institute of Economic Research
(NZIER) to review new evidence and with a focus on the taxation of sugar
sweetened beverages (SSBs).
Overall, the report examined 47 published scientific reports
or published studies of the theoretical or actual impact of sugar taxation on the
purchase of these products. Each study is considered in full and overall
conclusions are drawn. The report breaks down the complexity of the sugar tax
issue into 5 elements which underlie the logic of such taxes. It assumes
(1) that imposing a “sugar tax” will increase the price of
the taxed item, SSB’s;
(2) the increase in price will to lead to a reduction in
consumption of such beverages; (3) reduced SSB consumption will lead to a reduction
in calorie intake;
(4) lower caloric intakes will lead to lower adverse health risk
factors such as improved diabetes or hypertension management and
(5) in turn, that will lead to better health outcomes.
These 5 steps were considered in turn, taking all available
evidence into account.
Imposing a “sugar tax”
will increase the price of sugar sweetened beverages
There are two main possibilities here. The manufacturers of
SSBs could absorb the tax and make a loss. In the real world, those who sell SSB’s
also sell diet sweetened beverages and also juices and waters of various hues.
So, it is not beyond the bounds of possibility that the SSB manufacturer absorbs
most of the cost of the SSB tax thus protecting the consumer from a full price
hike on fizzy drinks while protecting their profits through marginally higher
prices on a range of SSB alternatives that they sell into the market (juices,
waters, diet drinks) .
Increased price of
sugar sweetened beverages will lead to a lower intake
Without wishing to delve too deeply into the econometric
arguments of the report, there is one critically important point made by the
authors. The models put forward in the sugar tax debate are focused on the
sensitivity of the overall market to
changes in the price of SSBs. However, the report points out that there is no
data on how the response shapes out at sub-group levels of the market. Will
high SSB consumers be more or less price sensitive than low SSB consumers? Will
prevailing body weight play a role in shaping price sensitivity? Will these two
factors interact such that overweight high consumers behave differently than
normal weight high consumers?
A lower sugar intake
will lead to a lower calorie intake.
The report points out that if the price of SSBs leads to a
lower intake of these products, it doesn’t necessarily follow that other untaxed
products might not fill the void. Indeed, human intervention studies, which
have surreptitiously lowered
the sugar levels of foods have found that energy intake remains more or less
constant with other foods filling the caloric gap. The biological data would
suggest that the caloric deficit made by reduced SSB consumption would be
largely, but not completely, compensated through higher intakes of many other
foods. Thus whatever the drop in calories will be, it will be only a fraction
of the present contribution of SSBs to calorie intake among SSB consumers. All
of this debate means nothing to the majority of the population that don’t
consume SSBs, across all age groups. We must accept that among SSB consumers,
such a tax will cause a drop in caloric intake but at just a fraction of the
present contribution of SSBs to calorie intake
If calorie intakes are
lowered, will body weight fall? If
bodyweight falls, will health outcomes inevitably follow.
The simple answer to both is yes. A small deficit of calories
over a long period of time would indeed create weight loss. One also has to
assume that weight loss will have some health benefits but one can also predict
that small changes and large changes in body weight, will have respectively
smaller and larger effects on health such as Type 2 diabetes or high blood
pressure.
The NZIER report itself, having considered all 47 studies on
the effectiveness of a tax on SSBs and examining each for the five elements of
the logic chain it set out from tax
imposition to measurable health benefits, concludes “As we noted in the section on frameworks, there are multiple steps in
the chain of intervention logic from the well-established principle that an
increase in the price of a good leads to a reduction in consumption of that
good and, all else equal, to an improvement in health outcomes…. Our conclusion is that the evidence base
gets weaker further along the chain of intervention logic… We have yet to see any clear evidence that
imposing a
sugar tax would meet a
comprehensive cost-benefit test”
All in all, the science and politics of sugar tax rolls on. Of
the three reports, that of the New Zealand Economics Institute is the one which
we need to focus most on. In particular, we need to focus on each of the links
in the chain it outlines for the sugar tax-obesity link and apply them
methodically to the monitoring of the soda tax and its effects on health
[3] Richard
D Smith, Laura Cornelsen, Diana Quirmbach, Susan A Jebb, Theresa M Marteau Are
sweet snacks more sensitive to price increases than sugar-sweetened beverages:
analysis of British food purchase data. BMJ Open 2018;8:e019788.
doi:10.1136/bmjopen-2017-019788
[4] Triona
Joyce, Sinead N. McCarthy and Michael J. Gibney. British Journal of Nutrition
(2008), 99, 1117–1126 Relationship between energy from added sugars and
frequency of added sugars intake in Irish children, teenagers and adults
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