Does taxing sugary drinks lead to health benefits?

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Benedette Cuffari, M.Sc.Jan 30 2025

New findings suggest that sugar-sweetened beverage taxes may contribute to weight reduction, particularly among young adults and certain demographic groups.

Study: City-Level Sugar-Sweetened Beverage Taxes and Changes in Adult Body Mass Index. Image Credit: fongbeerredhot / Shutterstock.com

In a recent study published in JAMA Network Open, researchers identify a significant association between sugar-sweetened beverage tax and body mass index (BMI) changes among adults living in Berkeley, California.     

How sugar-sweetened beverages drive obesity

In the United States, about 31% and 42% of adults are considered overweight and obese, respectively. An individual is considered overweight when their BMI exceeds 25 kg/m², whereas obesity is defined as having a BMI of over 30 kg/m².

Beyond its use as a classification, obesity is associated with serious health risks, including an increased risk of various diseases, particularly diabetes and cardiovascular disease, as well as overall morbidity and mortality.

Sugar-sweetened beverages are calorie-dense yet nutritionally poor, often leading to low satiety levels, excessive calorie intake, and weight gain. Unsurprisingly, their widespread consumption is a significant contributor to rising obesity rates in the United States.

Excise taxes are implemented on sugar-sweetened beverages as a policy intervention aiming to improve cardiometabolic conditions and generating revenue for public health initiatives. These taxes increase the purchase price of these beverages, thereby reducing purchasing and consumption.

A recent survey conducted in four U.S. cities with beverage taxes reported a one-third increase in beverage prices and one-third reduction in beverage purchases two years after the tax implementation. In fact, several studies investigating the health benefits of beverage tax suggest a reduction in BMI among adults; however, additional studies are needed to understand the long-term effects of beverage taxes on BMI and obesity.

Study design

The study cohort comprised 1,044,272 adults between 20 and 65 years of age who were members of Kaiser Permanente (KP). KP is an integrated health care delivery system that stores robust clinical data in its electronic health records, as well as sociodemographic and geographic information in its membership database.

Among the study participants, 178,931 were living in four California cities with beverage taxes including Albany, Berkeley, Oakland, and San Francisco. The study cohort was compared with the control cohort of the remaining 865,343 individuals residing in 40 California cities without beverage taxes.

Electronic health records were used to analyze changes in BMI and determine obesity prevalence from six years before tax implementation to four to six years after tax implementation.

Important observations

A significantly lower proportion of overweight or obese participants in cities with beverage taxes were identified as compared to those living in control cities. Cities with beverage taxes had higher proportions of Black and White participants and lower proportions of Hispanic participants. Nevertheless, no statistically significant change in BMI and obesity prevalence was observed before and after the tax implementation across four cities with a beverage tax as compared to control cities.

These associations were also stratified by city with beverage tax, age category, sex, race and ethnicity, and year of post-tax implementation. This analysis revealed a modest reduction in BMI among adults between 20 and 39 years of age, female participants, and White participants living in cities with beverage tax. The association between beverage tax and BMI change was statistically significant only for those living in Berkeley, with the strongest effect observed at the fifth year of tax implementation.

No significant differences in the prevalence of obesity were observed in the stratified analyses, except for a slight increase among the high-poverty subgroup.

Conclusions

The implementation of a sugar-sweetened beverage tax led to a reduction in BMI among adults belonging to specific demographic subgroups. The most significant impact of the beverage tax was observed among young adults between 20 to 39 years of age, who are the most frequent consumers of these beverages.

Among four California cities with beverage tax, Albany, Berkeley, and San Francisco, respectively, invested 100%, 92%, and 79% of their sugar-sweetened beverage tax revenue to health-related goals. Comparatively, Oakland divided allocations relatively evenly between human and community capital and health.

Berkeley is the first U.S. city to implement beverage tax, which has been attributed to 52% reduction in sugar-sweetened beverage consumption in Berkeley within three years of tax implementation. Moreove,r Berkeley created a commission of Berkeley residents to identify community needs and priorities, as well as advance grants for programs as early as six months after sugar-sweetened beverage tax implementation. These strategies may have significantly contributed to the observed reduction in BMI among adults living in Berkeley.

Other cities are also expected to gradually experience the health benefits of these initiatives. Thus, additional economic analyses are needed to understand the impact of these tax-supported programs on health and weight in the future.    

The study population was restricted to KP members with at least one BMI measurement before and after beverage tax implementation. This criterion may introduce selection bias and restrict the generalizability of the findings.

Future studies are also needed to determine the mechanisms of these associations to inform how sugar-sweetened beverage taxes could be more equitable for weight-related outcomes.