Fat chance: Obesity in SA is a complex, multifactorial problem that which cannot be tackled via a single intervention such as a tax on sugary beverages. Picture: ISTOCK
Fat chance: Obesity in SA is a complex, multifactorial problem that which cannot be tackled via a single intervention such as a tax on sugary beverages. Picture: ISTOCK

If pharmacists are not allowed to sell drugs to known drug addicts, why can’t McDonald’s refuse to sell burgers to obese individuals?" This joke, aired on a local radio station’s breakfast show, raises a good point.

If we’re going to tackle obesity through public health interventions, should the government go further than a tax on sugary beverages and restrict access to foods that are associated with an increase in obesity? Why not tax people for not exercising because of the burden they place on the health system later on?

Despite the logic, not many would agree to implement such measures based on scientific and moral arguments.

So, why then a sugar tax to reduce obesity?

Out of a range of possible interventions, the government has chosen a tax on sugar-sweetened beverages to try to enforce behavioural change.

A tax is just one of many "upstream" policy targets including service delivery, government spending and taxing, advocacy and the laws outlined in The Obesity Policy Action framework, a modification of the World Health Organisation’s (WHO) Global Strategy on Diet, Physical Activity and Health.

The framework identifies possible policy instruments available to governments that might influence risk factors associated with obesity.

The only other policy intervention to curb obesity in SA is an effort to implement physical education in schools.

During hearings into the sugar tax, we heard very little detail on what else the government plans to do to tackle obesity using other measures.

The government’s sugar tax argument is based on two premises: that consumption of sugar-sweetened beverages leads to obesity and the taxation of these products results in their reduced consumption. If the premises hold true, it leads to the conclusion that the taxation of sugar-sweetened beverages results in reduced obesity.

The government’s position is largely based on the first premise — that the consumption of sugar-sweetened beverages leads to obesity. Using evidence from Priority Cost Effective Lessons for Systems Strengthening SA, it concluded that the consumption of these drinks is associated with a 30% increase in the risk of diabetes mellitus and obesity in SA.

However, a meta-analysis of randomised control trials on the causal link between sugar consumption and obesity, published in the European Journal of Nutrition in February 2016, does not support the connection between sugar consumption at normal levels and obesity.

The average amount of sugar in a sugar-sweetened beverage equates to less than 3% of normal overall caloric intake for the average South African. This is less than the 10% recommended by the WHO.

If a person overconsumes these drinks, the sugar level would naturally increase to above normal. However, the link between overconsumption of a particular food or drink and likelihood of developing obesity is not unique to sugar.

Anything taken in excess is bad for one’s health. The overconsumption of fast foods such as deep-fried chicken or burgers and chips — common in SA — also leads to obesity.

So, while sugar-sweetened beverages do contribute to daily caloric intake, the normal consumption of them is not a risk factor for obesity.

Next, does taxation really reduce consumption of sugar-sweetened beverages? Evidence on this is contradictory.

A meta-analysis by Maria Escobar and colleagues, published in BMC Public Health in 2013, reported that the sugar-sweetened beverage tax was associated with reduced demand but increased demand for alternative beverages such as fruit juices.

After Mexico introduced a tax on sugary drinks, demand initially dropped, but this was found to be temporary, with sales of sugary drinks increasing to above pretax levels, according to the National Institute of Public Health.

Finally, does taxing sugar-sweetened beverages really reduce obesity? The arguments on the two premises above make this conclusion flawed.

Taxation of these drinks seems to be a tragedy of the commons – the idea that because my neighbour is doing it, I may as well do it too.

There is no evidence supporting this conclusion and such studies are difficult given the plethora of confounding variables. It is a narrow approach to obesity that could eventually send us down the slippery slope of taxing everything we can think of.

We started with the tobacco and alcohol tax, the so-called "sin" tax as a way of enforcing behavioural change.

With similar motivations, it’s now sugar tax.

Soon, we might see ourselves following the failed example of "fat tax" in terms of which studies similar to the one justifying the "sugar tax" are used, with the aim of enforcing behavioural change to reduce high-fat intake. Denmark introduced a tax on foods with high saturated fatty acids. It was abolished a year later. Such knee-jerk policies have a high risk of failure. Let’s not make the same mistake with a sugar tax.

Clearly, we cannot tax our way out of problems. Taxation as an intervention to foster behavioural change should, in my opinion, be a last resort.

The antecedents or basis of human behaviours can be identified and targeted by more effective interventions.

Understanding why people enjoy sugar and consume the foods and beverages they do means designing more effective mechanisms of action to change their behaviour.

In turn, this provides feedback to allow for the refinement of the intervention to maximise its efficiency.

Policies aimed at shaping the food and physical environments that would indirectly influence behaviour and positive health outcomes are a better alternative to tax.

In the South African context, for example, a "kota" (the street name for a quarter of a loaf of bread stuffed with sausage, fried chips, polony, atchar, cheese and so forth) is an easier, cheap and more accessible choice than a Greek salad.

Policies should, therefore, be aimed at making healthier food choices better and cheaper than unhealthy alternatives.

Potential policy action areas include restricting marketing of unhealthy food and encouraging physical activities in schools (mandatory physical education), workplaces, hospitals, prisons and communities.

To be effective, all these policies should be looked at through the prism of the determinants of the behaviours.

Obesity is a multifactorial condition that cannot be solved through a narrow approach such as the taxation of sugar-sweetened beverages.

The current strategic plan correctly identifies the risk factors that need to be tackled.

Dealing with these factors entails coming up with broad policies that at the same time respect individual liberties and that are nondiscriminatory — especially given SA’s history.

A collective effort through consultative forums with healthcare practitioners, nutritionists, industry, public health practitioners and the general public is likely to yield policies acceptable to both the state and society.

Dr Chawana is a senior programme manager for the Wits Health Consortium and a senior lecturer at Monash School of Public Health.

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