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Snack tax may be more effective than a sugary drink tax to tackle obesity

The effect was double that seen for a similar price increase on sugar sweetened drinks.
Caption: High sugar snacks. Credit: Christian Sinibaldi

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 new study published in the BMJ.

The research team, led by the London School of Hygiene & Tropical Medicine in conjunction with the University of Oxford and the University of Cambridge, 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 203g over one year.

Although positive health effects were found across all income and weight groups, they were greatest in low-income households and households where the main shopper was classified as obese.

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.

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.

Dr Pauline Scheelbeek, lead author from the London School of Hygiene & Tropical Medicine, said: “The use of taxes to lower sugar and energy intake have mainly focused on sugar sweetened drinks. Our work found that price increases in high sugar snacks such as chocolates, confectionery, cookies and cake could make an important contribution to government policies to tackle obesity, and reduce existing gaps in healthy life expectancy.”

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.

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% after the first year. This suggests that price increases in high sugar snacks could also make an important contribution to reducing health inequalities driven by diet-related disease.

Dr Scheelbeek said: “There is no silver bullet for tackling obesity and improving nutritional health in the UK. However our study suggests fiscal interventions to discourage purchase of high sugar snacks could play an important role in the integrative approach required.”

The authors acknowledge limitations of the study including 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.

The study was funded by the National Institute for Health Research.

Publication

Pauline F D Scheelbeek, Laura Cornelsen, Theresa M Marteau, Susan A Jebb, Richard D Smith. Potential impact on prevalence of obesity in the UK of a 20% price increase in high sugar snacks: modelling study. BMJ. DOI:10.1136/bmj.l4786