April 8, 2021

A new study shows that South Africa’s 2018 tax on sugary beverages led to a reduction in purchases of the beverages, which could mean purchasers are consuming less excess sugar and fewer calories.

Dr. Barry Popkin

Dr. Barry Popkin

Dr. Shu Wen Ng

Dr. Shu Wen Ng

Shu Wen Ng, PhD, associate professor and Distinguished Scholar in Public Health Nutrition at the UNC Gillings School of Global Public Health, is a lead author of “Changes in beverage purchases following the announcement and implementation of South Africa’s Health Promotion Levy: an observational study,” which was published April 8 in The Lancet Planetary Health. Barry Popkin, PhD, W. R. Kenan Jr. Distinguished Professor at the Gillings School, is a co-author on the paper, which was written in collaboration with partners at the University of the Witwatersrand, the London School of Economics and the University of the Western Cape.

South Africa faces an increasing burden of noncommunicable diseases such as diabetes, hypertension, cardiovascular disease and cancers — diseases that research shows can be linked to increased consumption of sugar, particularly from beverages. Other countries, including Mexico, have used policies such as taxation to successfully curb sugary beverage consumption.

South Africa’s 2018 Health Promotion Levy placed a tax on sugary beverages with the tax amount related to the amount of sugar in each drink. This is the first study to evaluate the impact of the South African tax on sugar and caloric intake.

Researchers examined the nutritional data of more than 3,000 households’ purchases before and after the tax to assess any changes in daily sugar intake, calories consumed, and volume of taxed and non-taxed beverages purchased. They found a 51% reduction in sugar, a 52% reduction in calories and a 29% reduction in volume of beverages purchased per person per day following implementation of the tax. They also found that the relative reduction in the sugar content of taxable beverages was larger than that for volume, showing that the industry likely reformulated their products in response to the tax.

The researchers also analyzed differences in purchasing behavior by household socioeconomic status. They found that lower socioeconomic status households purchased more taxable beverages prior to the announcement of the tax than did higher socioeconomic status households, and lower socioeconomic status households experienced larger purchase reductions after the tax implementation.

“These results back up the impact we’ve seen from similar policies in other countries — that beverage taxes based on sugar content can help reduce excessive sugar and energy intake,” says Ng. “Importantly, this shows that lower income households, which experience a greater burden of obesity, diabetes, hypertension and other nutrition-related noncommunicable diseases, benefit greatly from this law.”

“Consistent with evaluations in other countries with sugar-sweetened beverages taxes, we found that taxing sugary drinks is an effective public health strategy to reduce the burden of health conditions linked to overconsumption of sugar,” Popkin notes.

Ng and Popkin are part of the Global Food Research Program at UNC, a project of the Carolina Population Center that collaborates with partners around the globe to carefully evaluate food and nutrition policies and develop in-depth, longitudinal research on large-scale obesity prevention efforts.

Contact the UNC Gillings School of Global Public Health communications team at sphcomm@unc.edu.

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