Taxes on Sugar-Sweetened Beverages to Reduce Overweight and Obesity in Middle-Income Countries: A Systematic Review

Abstract

Background: The consumption of sugar-sweetened beverages (SSBs), which can lead to weight gain, is rising in middle-income countries (MICs). Taxing SSBs may help address this challenge. Systematic reviews focused on high-income countries indicate that taxing SSBs may reduce SSB consumption. Responsiveness to price changes may differ in MICs, where governments are considering the tax. To help inform their policy decisions, this review compiles evidence from MICs, assessing post-tax price increases (objective 1), changes in demand for SSBs and other products, overall and by socio-economic groups (objective 2), and effects on overweight and obesity prevalence (objective 3).

Methods and findings: We conducted a systematic review on the effectiveness of SSB taxation in MICs (1990-2016) and identified nine studies from Brazil, Ecuador, India, Mexico, Peru, and South Africa. Estimates for own-price elasticity ranged from -0.6 to -1.2, and decreases in SSB consumption ranged from 5 to 39 kilojoules per person per day given a 10% increase in SSB prices. The review found that milk is a likely substitute, and foods prepared away from home, snacks, and candy are likely complements to SSBs. A quasi-experimental study and two modeling studies also found a negative relationship between SSB prices and obesity outcomes after accounting for substitution effects. Estimates are consistent despite variation in baseline obesity prevalence and per person per day consumption of SSBs across countries studied.

Conclusions: The review indicates that taxing SSBs will increase the prices of SSBs, especially sugary soda, in markets with few producers. Taxing SSBs will also reduce net energy intake by enough to prevent further growth in obesity prevalence, but not to reduce population weight permanently. Additional research using better survey data and stronger study designs is needed to ascertain the long-term effectiveness of an SSB tax on obesity prevalence in MICs.

Fig 1. Logical Pathway from Taxing SSBs to Public Health Impact.

Fig 2. Documentation of Study Search and Selection.

Fig 3. Own-Price Elasticities of SSBs and Change in kJ PPPD Given a 10% Price Increase.

*Change in kJ PPPD given a 10% price change was calculated from study estimates using unit conversions based on the identities and assumptions presented in the methods section; **estimates come from the following studies listed as: author, (year of study), country in (year of estimate): 1 -Andreyeva et al. (2010) United States 1938–2007 [47]; 2—Escobar (2012) Global 2000–2013 [25]; 3—Colchero (2016) Mexico in 2015 [35]; 4—Ritter Burga (2016) Peru 1997–2001 [34]; 5—Barquera (2008) Mexico in 2006; 6—Barquera (2008) Mexico in 1998; 7—Barquera (2008) Mexico in 1989 [36]; 8 –Basu (2014) India 2014–2023 [40]; 9—Claro (2012) in 2003 [39]; 10—Colchero (2015) Mexico across 2006, 2008, and 2010 [42]; 11—Manyema (2014) South Africa in 2012 [17]; 12—Paraje (2016) Ecuador in 2012 [44]; ***findings based on observed increase in prices of soda; †missing estimates: Colchero (2016) results do not allow for a precise estimate of own-PE [35]; Barquera (2008) only provided analysis B estimates for 2006 data [36]; Colchero (2015) does not include baseline estimates of SSB consumption or other estimates needed for standardization [42]; Manyema (2014) [17] uses meta-analysis estimates for own-PE from Escobar (2012) [25], presented at the top of the figure; Grogger (2015) [41] was not included as its estimates do not include own-PE estimates and do not allow for standardization.