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Effect was double that seen for similar price increase on sugar sweetened drinks

© Photo by Court Prather on Unsplash

Taxing high sugar snacks such as biscuits, cakes, and sweets might be more effective at reducing obesity levels than increasing the price of sugar sweetened drinks, suggests a study published by The BMJ today.

From the London School of Hygiene and Tropical Medicine and the Universities of Cambridge, Oxford and Exeter, the researcher team say this option “is worthy of further research and consideration as part of an integrated approach to tackling obesity.”

Obesity rates are increasing across the world. In the UK, obesity is estimated to affect around 1 in every 4 adults and around 1 in every 5 children aged 10 to 11, with higher rates among those living in more deprived areas.

The use of taxes to lower sugar and energy intake have mainly focused on sugar sweetened drinks. But in the UK, high sugar snacks, such as biscuits, cakes, chocolates and sweets make up more free sugar and energy intake than sugary drinks.

Reducing purchases of high sugar snacks therefore has the potential to make a greater impact on population health than reducing the purchase of sugary drinks.

“To date, public policy to improve the nutritional quality of the food supply has relied heavily on reformulation. This has worked well for sugary drinks, where reformulation to produce very similar but low sugar products results in a highly acceptable alternative. But the same is not so for many other high sugar snacks, especially confectionary, and the only real option to cut calories is for people to eat less. 

"We know that price rises on unhealthy products – tobacco, alcohol and sugary drinks – are some of the most effective but least popular interventions for improving health. However the challenge for public health is that evidence of effectiveness of fiscal policies mostly accumulates after the policy has been introduced. For new policies we need an open-minded approach to the nature of evidence – combining plausible mechanisms, modelling and case-studies from other countries or similar scenarios. The evidence we present here - that price increases on high sugar snacks could significantly reduce purchases, should encourage policymakers as they consider the next steps in the strategy to tackle obesity.”

Co-author Professor Susan Jebb, Nuffield Department of Primary Care Health Sciences.

To explore this in more detail, researchers used economic modelling to assess the impact of a 20% price increase on high sugar snack foods in the UK. 

Modelling was based on food purchase data for 36,324 UK households and National Diet and Nutrition Survey data for 2,544 adults. Results were grouped by household income and body mass index (BMI) to estimate changes in weight and prevalence of obesity over one year.

The results suggest that for all income groups combined, increasing the price of biscuits, cakes, chocolates, and sweets by 20% would reduce annual average energy intake by around 8,900 calories, leading to an average weight loss of 1.3 kg over one year. 

In contrast, a similar price increase on sugary drinks would result in an average weight loss of just 203 g over one year.

What’s more, the model predicts that the impact of the price increase would be largest in low income households with the highest rates of obesity, suggesting that taxing high sugar snacks could help to reduce health inequalities driven by diet related diseases, say the researchers.

They point to some possible study limitations, such as the relatively short, one-year, time-frame over which weight changes were modelled, but say findings were based on information from high quality databases and remained largely unchanged after varying some key assumptions.

As such, they say that a 20% price increase in high sugar snacks “has the potential to reduce overall energy purchased among all body mass index and income groups in the UK, leading to an estimated population level reduction in obesity prevalence of 2.7 percentage points after the first year.”

“The results also suggest that price increases in high sugar snacks could also make an important contribution to reducing health inequalities driven by diet related disease,” they conclude. 

Read more:

Potential impact on prevalence of obesity in the UK of a 20% price increase in high sugar snacks: modelling study
The BMJ 2019

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