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.