The study used mathematical modelling alongside data on how soft drink consumption affects energy intake and how energy intake affects obesity prevalence. It estimated that a 20% tax could reduce sugar sweetened drink consumption by 15%, and would have the greatest effect on people aged under 30, as they consume the most soft drinks. Contrary to the findings from previous studies, the researchers claim that health benefits would be similar for all UK income groups.
They added that although a 20% tax could reduce the number of obese people in the UK by about 180,000, it was not a cure-all.
“The effects on obesity are relatively modest,” the study’s authors wrote. “This is in part because sugar sweetened drinks are not consumed in large amounts by the older adult population in whom obesity is more prevalent and causes more disease. Our study also shows that although such a tax would not be a panacea for obesity, it could make a useful contribution to a multi-pronged strategy to combat obesity and other diet related disease.”
Larger effect from fruit and veg
The authors pointed to a 2010 study, which predicted that sugary drink consumption contributes a relatively small amount to UK morbidity compared with low fruit and vegetable consumption – 28,000 disability adjusted life years, versus 1,130,000.
“Using revenue from a sugar sweetened drink tax to reduce the prices of fruit and vegetables is a potential mechanism for further improving population health,” they wrote, adding that a 20% tax could raise £276m a year (about €326m).
The British Soft Drinks Association (BSDA) claims that other studies have questioned the effect of a sugared soft drink tax on both consumption and obesity rates.
“There’s ample evidence to suggest that taxing soft drinks won’t curb obesity, not least because its causes are far more complex than this simplistic approach implies,” said BSDA director general Gavin Partington.
“Indeed the latest official guidance from the National Institute for Health and Care Excellence points to the need to look at overall diet and lifestyle. Trying to blame one set of products is misguided, particularly when they comprise a mere 2% of calories in the average diet.”
The study estimated calorie reduction resulting from taxation at about half that of a similar US-based study, mainly because average UK consumption of sugar-sweetened drinks tends to be lower than average US consumption.
The full study is available online here.