Are intentions to change, policy awareness, or health knowledge related to changes in dietary intake following a sugar-sweetened beverage tax in South Africa? A before-and-after study

Abstract

Background In April 2018, South Africa implemented the Health Promotion Levy (HPL), one of the first sugar-sweetened beverage (SSB) taxes to be based on each gram of sugar (beyond 4 g/100mL). The objectives of this study were to examine whether the psychological constructs tax awareness, SSB knowledge, SSB risk perception, and intentions to reduce SSB intake were associated with taxed beverage intake, whether they changed from pre- to post-tax, and whether they modified the effect of the HPL. Methods We collected single day 24-hour dietary recalls surveyed from repeat cross-sectional surveys of adults aged 18–39 years in Langa, South Africa. Participants were recruited in February-March 2018 (pre-tax, N = 2,481) and February-March 2019 (post-tax, N = 2,507) using door-to-door sampling. Surveys measured tax awareness, SSB knowledge, SSB risk perception, and intention to reduce SSB intake. SSB intake was estimated using a two-part model. To examine changes over time, logistic regression models were used for binary outcomes (tax awareness and intention to reduce SSB consumption) and linear regression models for continuous outcomes (SSB knowledge SSB risk perceptions). Effect modification was tested using interaction terms for each psychological construct with time. Results No constructs were associated with SSB intake at baseline. At post-tax, the predicted probability to consume taxed beverages was 33.5% (95% CI 28.5–38.5%) for those who expressed an intention to reduce SSB intake compared to 45.9% (95% CI 43.7–48.1%) for those who did not. Among consumers, intending to reduce SSB intake was associated with 55 (95% CI 28 to 82) kcal/capita/day less SSBs consumed. Tax awareness, SSB knowledge, and SSB risk perception increased by a small amount from pre- to post-tax. Intentions to reduce SSB intake was lower in the post-tax period. The tax effect on SSB intake was modified by SSB knowledge and intention to reduce SSB intake, with higher levels of each associated with lower SSB intake. Conclusion After the South African SSB tax was implemented, SSB knowledge and risk perception increased slightly, tax awareness remained low, and only SSB knowledge and behavioral intention to change were significantly associated with taxed beverage intake among participants recruited from a low-income South African township.

Attitudes of Chinese residents toward sugar-sweetened beverage tax and their willingness to pay: a cross-sectional survey

“…In the present study, the marginal effect analysis revealed that a one-level increase in SSB awareness could increase the probability of supporting SSB taxes by 17%. Compared with other factors, increased SSB awareness could greatly promote tax support, which is consistent with the result of a study conducted in South Africa (33). Further research should be conducted on various aspects, including residents' attitudes, countermeasures by enterprises, tax effects, and tax systems, which would provide a basis for the formulation of relevant policies.…”

Economic priorities over population health: A political dilemma in addressing noncommunicable diseases in developing countries

“…In South Africa where the government introduced the health promotion levy and a tax imposed on sugar to increase purchasing cost of SSB and discourage consumption, still citizens did not significantly reduce their demands. The study identified low awareness on the motives of the levy, and were influenced by addiction and branding effect to purchase SSB 36,37 . Moreover, implementation of taxation in sugar based on sugar content might counteract this effect 38 …”

“…The study identified low awareness on the motives of the levy, and were influenced by addiction and branding effect to purchase SSB. 36,37 Moreover, implementation of taxation in sugar based on sugar content might counteract this effect. 38 The introduction of taxation that can have a positive effect on the public health faces challenges due to the conflict of interest from government authorities and different globalization stakeholders.…”

“…The study identified low awareness on the motives of the levy, and were influenced by addiction and branding effect to purchase SSB. 36 , 37 Moreover, implementation of taxation in sugar based on sugar content might counteract this effect. 38 …”