Mark Harris. Obesity: it is time to tax sugar sweetened beverages?

Obesity rates are increasing in the Australian population (Figure 1). There is a widening socioeconomic gap with low socioeconomic groups having the highest rates. There is some evidence that obesity rates in children may be levelling off but not in low socioeconomic status children. Overweight and obesity contributes significantly to the burden of disease (about 9% in Australia at present), loss of quality of life and premature mortality (death before completing expected life span) in Australia.

Obesity is a complex problem requiring complex solutions. There is no magic bullet. Ultimately obesity occurs because of an imbalance in the amount of energy consumed and absorbed in the gut and the amount used up as part of metabolism as well as through physical activity. There are many complex factors influencing this imbalance across the lifecycle (Figure 2). These are in turn influenced by many factors in the social and economic environment. It is easy to think that it is all just too hard at one extreme or that it can be simply address by individual will power at the other extreme.

At a population level, there are a number of strategies that can achieve improvements. These involve changes in the way we live. While on their own any one strategy is unlikely to solve the problem of obesity, collectively they may contribute to further slowing or reversing the rise in the prevalence of obesity in the Australian community. One such strategy is to reduce sugar sweetened beverages (SSB). In the UK government will apply a levy on SSBs from 2018 joining a number of other countries including France, Belgium, Norway and Sweden.

There are three main reasons for focusing on on SSBs:

  1. SSBs contribute significantly to the energy intake of Australians.   The Australian Health Survey in 2011-12 found that the reported consumption of sweetened beverages increased with age across childhood, with 61% of teenagers aged 14-18 years reporting drinking it on the previous day. Overall teenagers consumed 6% of their energy from SSBs. Rates are higher in low SES people.
  2. SSBs have no nutritional value (they are so called “empty calories”). Furthermore they tend not to cause satiety (as does food). There is an association between levels of SSB consumption and weight gain among both adults and children. In Australia water is a plentiful, safe and cheap alternative.
  3. Modelling and some experience from other countries suggests that reducing SSBs would have a significant effect weight gain. For example removing SSB from the diet of teenagers would reduce their energy intake by about 10% thus contributing to reduced rates of overweight and obesity in this age group.

How can a reducing in SSB consumption be achieved? It is not easy. SSB are ubiquitous in the Australian environment. Dispensing machines are located almost everywhere in addition to availability through supermarkets, cafes and restaurants. A number of strategies have been proposed and attempted:

  • Reduce or ban advertising especially for children. Advertising on SSB exceeds $50m per annum in Australia and children are currently not protected from this advertising.
  • Educate the population about the risks of SSB through media campaigns. There is evidence that consumption of SSB has decreased since 1995 especially in children. However this may also contribute to inequities as the change has been greatest among higher SES groups.
  • Remove SSB from school and health service canteens and dispensers. This may be effective for primary school but is less effective for high school especially as children can access SSB outside the school grounds.
  • Reduce the size of SSB containers (eg new smaller soft drink cans).
  • Increase tax on SSB. This has been successful in tobacco control. Modelling suggests that this would need to increase prices by 20% to be effective.

What are the possible unintended consequences of these actions? It is possible that a tax may economically disadvantage the poor who have higher SSB consumption. This can be partly addressed by education about use of water and could be offset by reduced tax on healthy alternatives such as fresh fruit and vegetables. These efforts may displace consumption onto other energy dense drinks without added sugar (fruit juices, milk drinks). This may have already occurred with fruit juice but there is no evidence for other drinks.

So what is the way forward?   A range of health groups have recommended social marketing campaigns, restrictions of children’s exposure through marketing and in schools and sporting facilities, reduced availability it workplaces, government institutions, health care facilities and public places and exploration of tax increases. All these are likely to be necessary to reduce SSB consumption sufficiently to reduce obesity rates.

These measures are, of course, likely to meet resistance from industry groups. They argue that this is a matter for individual choice and not for government regulation. However the socioeconomic gradient in SSB consumption and its effects on weight and the burden of disease both for individuals and the whole community suggest that public health action is warranted.   With its high impact on children, the consequences of inaction are likely to be significant across generations.

 

 

References

Australian Bureau of Statistics: 4364.0.55.007 – Australian Health Survey: Nutrition First Results – Foods and Nutrients, 2011-12

Malik VS, Schulze MB, Hu FB. Intake of sugar-sweetened beverages and weight gain: a systematic review. American Journal of Clinical Nutrition 2006 Aug;84(2):274-88

Lustig RH, Schmidt LA, Brindis CD. The toxic truth about sugar. Nature 2012; 482: 27-29

Re-think sugary drink. Consensus Statement on sugar-sweetened beverages. Cancer Council Australia, National Heart Foundation, Diabetes Australia, Nutrition Australia, YMCA, Australian Dental Association, Dental Health Services Victoria, Obesity Policy Coalition. http://www.rethinksugarydrink.org.au/downloads/Consensus_position_statement.pdf

Figure 1: Overweight or obese, persons aged 18 and over, 1995, 2007–08 and 2011–12

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Notes:

  1. Age-standardised to the 2001 Australian population.
  2. Overweight and obesity classification based on measured height and weight in all 3 surveys.

 

Source: AIHW 2012, ABS 2013.

 

Figure 2: Some of the causal factors involved in weight gain.

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Professor Mark Harris is from the Centre for Primary Health Care and Equity, UNSW. 

 

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