The Impact of Seattle's Sugar-Sweetened Beverage Tax on Substitution to Sweets and Salty Snacks

Effectiveness of implemented global dietary interventions: a scoping review of fiscal policies

BACKGROUND

Although the World Health Organisation (WHO) has proposed the use of fiscal policies to mitigate consumption externalities such as overweight and obesity-related diseases, very little is known about the impacts of the different types and framing of national and/or regional fiscal policies that have been implemented over the years. There is the need to provide up-to-date evidence on the impact of fiscal policies that have been enacted and implemented across the globe.

METHODS

We conducted a scoping review of all implemented government fiscal policies in the food and drinks sector to identify the different types of fiscal policies that exist and the scope of their impact on consumers as well as the food environment. Electronic databases such as the Web of Science and Google Scholar were used to search for appropriate literature on the topic. A total of 4,191 articles were retrieved and 127 were synthesized and charted for emerging themes.

RESULTS

The results from this review were synthesized in MS Excel following Arksey & O'Malley (2005). Emerging themes were identified across different countries/settings for synthesis. The results confirms that fiscal policies improve consumers' health; increase the prices of foods that are high in fats, sugar, and salt; increase government revenue; and shift consumption and purchases towards healthier and untaxed foods.

CONCLUSION

Governments already have the optimum tool required to effect changes in consumer behaviour and the food environment.

The implications of policy modeling assumptions for the projected impact of sugar-sweetened beverage taxation on body weight and type 2 diabetes in Germany

BACKGROUND

Evaluating sugar-sweetened beverage (SSB) taxation often relies on simulation models. We assess how assumptions about the response to SSB taxation affect the projected body weight change and subsequent health and economic impacts related to type 2 diabetes mellitus (T2DM) using Germany as an example.

METHODS

In the main analysis, we estimated changes in energy intake by age and sex under a 20% value-added tax on SSBs in Germany using marginal price elasticities (PE) and applied an energy equilibrium model to predict body weight changes. We then quantified the impact of several assumption modifications: SSB own-PE adjusted for consumption (M1)/based on alternative meta-analysis (M2); SSB consumption adjusted for underreporting (M3); substitution via marginal (M4a) or adjusted (M4b) cross-PE/as % of calorie change (M4c). We also assessed scenarios with alternative tax rates of 10% (S1) or 30% (S2) and including fruit juice (S3). We calculated overweight and obesity rates per modification and scenario. We simulated the impact on T2DM, associated healthcare costs, and disability-adjusted life years (DALYs) over the lifetime of the 2011 German adult population with a Markov model. Data included official demographics, national surveys, and meta-analyses.

RESULTS

A 20% value-added tax in Germany could reduce the number of men and women with obesity by 210,800 [138,800; 294,100] and 80,800 [45,100; 123,300], respectively. Over the population's lifetime, this would lead to modest T2DM-related health and economic impacts (76,700 DALYs [42,500; 120,600] averted; €2.37 billion [1.33; 3.71] costs saved). Policy impacts varied highly across modifications (all in DALYs averted): (M1) 94,800 [51,500; 150,700]; (M2) 164,200 [99,500; 243,500]; (M3) 52,600 [22,500; 91,100]; (M4a) -18,100 [-111,500; 68,300]; (M4b) 25,800 [-31,400; 81,500]; (M4c) 46,700 [25,300; 77,200]. The variability in policy impact related to modifications was similar to the variability between alternative policy scenarios (all in DALYs averted): (S1) 26,400 [9,300; 47,600]; (S2) 126,200 [73,600; 194,500]; (S3) 342,200 [234,200; 430,400].

CONCLUSIONS

Predicted body weight reductions under SSB taxation are sensitive to assumptions by researchers often needed due to data limitations. Because this variability propagates to estimates of health and economic impacts, the resulting structural uncertainty should be considered when using results in decision-making.

Evaluation of the sugar-sweetened beverage tax in Oakland, United States, 2015-2019: A quasi-experimental and cost-effectiveness study

BACKGROUND

While a 2021 federal commission recommended that the United States government levy a sugar-sweetened beverage (SSB) tax to improve diabetes prevention and control efforts, evidence is limited regarding the longer-term impacts of SSB taxes on SSB purchases, health outcomes, costs, and cost-effectiveness. This study estimates the impact and cost-effectiveness of an SSB tax levied in Oakland, California.

METHODS AND FINDINGS

An SSB tax ($0.01/oz) was implemented on July 1, 2017, in Oakland. The main sample of sales data included 11,627 beverage products, 316 stores, and 172,985,767 product-store-month observations. The main analysis, a longitudinal quasi-experimental difference-in-differences approach, compared changes in beverage purchases at stores in Oakland versus Richmond, California (a nontaxed comparator in the same market area) before and 30 months after tax implementation (through December 31, 2019). Additional estimates used synthetic control methods with comparator stores in Los Angeles, California. Estimates were inputted into a closed-cohort microsimulation model to estimate quality-adjusted life years (QALYs) and societal costs (in Oakland) from 6 SSB-associated disease outcomes. In the main analysis, SSB purchases declined by 26.8% (95% CI -39.0 to -14.7, p < 0.001) in Oakland after tax implementation, compared with Richmond. There were no detectable changes in purchases of untaxed beverages or sweet snacks or purchases in border areas surrounding cities. In the synthetic control analysis, declines in SSB purchases were similar to the main analysis (-22.4%, 95% CI -41.7% to -3.0%, p = 0.04). The estimated changes in SSB purchases, when translated into declines in consumption, would be expected to accrue QALYs (94 per 10,000 residents) and significant societal cost savings (>$100,000 per 10,000 residents) over 10 years, with greater gains over a lifetime horizon. Study limitations include a lack of SSB consumption data and use of sales data primarily from chain stores.

CONCLUSIONS

An SSB tax levied in Oakland was associated with a substantial decline in volume of SSBs purchased, an association that was sustained more than 2 years after tax implementation. Our study suggests that SSB taxes are effective policy instruments for improving health and generating significant cost savings for society.

Estimating the impact of nutrition and physical activity policies with quasi-experimental methods and simulation modelling: an integrative review of methods, challenges and synergies

BACKGROUND

The promotion of healthy lifestyles has high priority on the global public health agenda. Evidence on the real-world (cost-)effectiveness of policies addressing nutrition and physical activity is needed. To estimate short-term policy impacts, quasi-experimental methods using observational data are useful, while simulation models can estimate long-term impacts. We review the methods, challenges and potential synergies of both approaches for the evaluation of nutrition and physical activity policies.

METHODS

We performed an integrative review applying purposive literature sampling techniques to synthesize original articles, systematic reviews and lessons learned from public international workshops conducted within the European Union Policy Evaluation Network.

RESULTS

We highlight data requirements for policy evaluations, discuss the distinct assumptions of instrumental variable, difference-in-difference, and regression discontinuity designs and describe the necessary robustness and falsification analyses to test them. Further, we summarize the specific assumptions of comparative risk assessment and Markov state-transition simulation models, including their extension to microsimulation. We describe the advantages and limitations of these modelling approaches and discuss future directions, such as the adequate consideration of heterogeneous policy responses. Finally, we highlight how quasi-experimental and simulation modelling methods can be integrated into an evidence cycle for policy evaluation.

CONCLUSIONS

Assumptions of quasi-experimental and simulation modelling methods in policy evaluations should be credible, rigorously tested and transparently communicated. Both approaches can be applied synergistically within a coherent framework to compare policy implementation scenarios and improve the estimation of nutrition and physical activity policy impacts, including their distribution across population sub-groups.

Decomposing consumer and producer effects on sugar from beverage purchases after a sugar-based tax on beverages in South Africa

Growing global concern about obesity and diet-related non-communicable diseases has raised interest in fiscal policy as a tool to reduce this disease burden and its social costs, especially excise taxes on sugar-sweetened beverages (SSBs). Of particular interest have been nutrient-based taxes to improve diet quality. These can incentivize producers to reformulate existing products and introduce healthier alternatives into their ranges. In 2018, South Africa adopted a sugar-based tax on SSBs, the Health Promotion Levy (HPL). Early findings suggest that purchases of higher-sugar taxable beverages fell and purchases of no- and lower-sugar beverages increased, alongside significant reductions in the sugar content of overall beverage purchases. However, underlying these changes are consumption shifts as well as product reformulation and changes in producers' product portfolios. Drawing on a household scanner dataset, this study employed a descriptive approach to decompose changes in the sugar content of households' non-alcoholic beverage purchases into producer factors (reformulation and product entry and exit) and consumer factors (product switching and volume changes as a result of price changes, changing preferences, or other factors). We look at these factors as the tax was announced and implemented across a sample of over 3000 South African households, and then by Living Standard Measures (LSM) groups (middle vs. high). The sugar content of beverage purchases fell by 4.9 g/capita/day overall, a 32% decrease. Taken in isolation, consumer switching and volume changes together led to a reduction equivalent to 71% of the total change, while reformulation accounted for a decrease equal to 34% of that change. Middle-LSM households experienced larger reductions than high-LSM households due to larger changes on the consumer side. For both LSM groups, reformulation-led reductions mostly occurred after implementation, and most changes came from taxable beverage purchases. As sugary drink tax designs evolve with broader implementation globally, understanding both supply- and demand-side factors will help to better assess the population and equity potential of these policies.

Purchases of Nontaxed Foods, Beverages, and Alcohol in a Longitudinal Cohort After Implementation of the Philadelphia Beverage Tax

BACKGROUND

Evidence suggests that sweetened beverage taxes reduce taxed beverage purchases, but few studies have used individual-level data to assess whether these taxes affect purchases of nontaxed foods, beverages, and alcohol. Additionally, research has not examined whether sweetened beverage taxes influence restaurant purchases.

OBJECTIVES

We assessed changes in individuals' purchases of taxed beverage types; low-calorie/low-added-sugar nontaxed beverages; high-calorie/high-added-sugar nontaxed beverages, foods, and alcohol; and beverages from restaurants following implementation of the 1.5 cent-per-ounce Philadelphia sweetened beverage tax.

METHODS

A longitudinal cohort of adult sugar-sweetened beverage consumers in Philadelphia (n = 306; 67% female; mean age: 43.9 years) and Baltimore (n = 297; comparison city without a beverage tax; 58% female; mean age: 41.7 years) submitted all food and beverage receipts during 2-week periods at baseline and at 3, 6, and 12 months posttax. Difference-in-differences analyses compared changes in purchases from pre- to posttax in Philadelphia to changes in Baltimore.

RESULTS

Purchases of taxed juice drinks [ratio of incidence rate ratios (RIRR) = 0.62; 95% CI, 0.42-0.91], but not other taxed beverage types, decreased in Philadelphia compared to Baltimore following the tax. Analyses did not find changes in purchases of low-calorie/low-added-sugar nontaxed beverages, such as water or milk. Additionally, analyses did not find increases in purchases of most high-calorie/high-added-sugar nontaxed products, including alcohol, juice, candy, sweet snacks, salty snacks, and desserts. Purchases of beverage concentrates increased in Philadelphia (RIRR = 2.22; 95% CI, 1.39-3.54).

CONCLUSIONS

In this difference-in-differences analysis, the Philadelphia beverage tax was associated with reduced purchases of taxed juice drinks. Purchases of beverage concentrates increased after the tax, but no increases were observed for other high-calorie/high-added-sugar nontaxed foods, beverages, or alcohol.

Evaluation of Changes in Grams of Sugar Sold After the Implementation of the Seattle Sweetened Beverage Tax

IMPORTANCE

Adults and children routinely exceed recommended intake amounts of added sugars established by dietary guidelines. Taxes are used as a policy tool to reduce demand for sugar-sweetened beverages (SSBs) given consumption-related adverse health outcomes but may induce substitution to other sources of added sugars.

OBJECTIVE

To examine the extent to which changes in grams of sugar sold from taxed beverages may be offset by changes in grams of sugar sold from untaxed beverages, sweets, and stand-alone sugar after the implementation of the Seattle, Washington, Sweetened Beverage Tax (SBT) on January 1, 2018.

DESIGN, SETTING, AND PARTICIPANTS

This study used difference-in-differences analyses to examine changes in grams of sugar sold from taxed and untaxed products in Seattle compared with Portland, Oregon, at year 1 and year 2 post tax. This study used Nielsen scanner data from supermarkets and mass merchandise as well as grocery, drug, convenience, and dollar stores on unit sales and measurements for beverage and food product universal product codes (UPCs) for each site for the pretax period (January 8-December 30, 2017) and the corresponding weeks in year 1 post tax (2018) and in year 2 post tax (2019). Nutritional analyses assessed grams of sugar for each UPC. The analytical balanced sample included 1326 taxed beverage UPCs, 239 untaxed beverage UPCs, 2054 sweets UPCs, and 81 stand-alone sugar UPCs. Statistical analysis was performed from January to August 2021.

EXPOSURES

Implementation of the Seattle SBT.

MAIN OUTCOMES AND MEASURES

Changes in grams of sugar sold from taxed beverages, untaxed beverages, sweets, and stand-alone sugar.

RESULTS

At both year 1 and year 2 post tax in Seattle compared with Portland, grams of sugar sold from taxed beverages decreased 23% (year 2 posttax ratio of incidence rate ratios [RIRR] = 0.77; 95% CI, 0.73-0.80). Sugar sold from untaxed beverages increased at year 1 post tax by 4% (RIRR = 1.04; 95% CI, 1.00-1.07) with no change at year 2 post tax. Sugar sold from sweets increased by 4% at both year 1 and year 2 post tax (year 2 posttax RIRR = 1.04; 95% CI, 1.03-1.06). There were no changes in stand-alone sugar sold.

CONCLUSIONS AND RELEVANCE

This study using difference-in-differences analysis found a net 19% reduction in grams of sugar sold from taxed SSBs at year 2 post tax after accounting for changes in sugar sold from untaxed beverages, sweets, and stand-alone sugar. These results suggest that SSB taxes may effectively yield permanent reductions in added sugars sold from SSBs in food stores.