Changes in consumer purchasing patterns at New York City chain restaurants following adoption of the sodium warning icon rule, 2015-2017

Abstract

In 2016, New York City (NYC) began enforcing a sodium warning regulation at chain restaurants, requiring placement of an icon next to any menu item containing ≥2, 300 mg sodium. As shifts in consumer purchases are a potential outcome of menu labeling, we investigated whether high-sodium purchases from NYC chains changed following policy implementation. Using receipts for verification, consumer purchases were assessed at 2 full-service (FSR) and 2 quick-service (QSR) chain restaurants in NYC and Yonkers, NY, which did not implement sodium menu labeling, in 2015 and 2017. Primary outcomes included the proportion of respondents purchasing high-sodium item(s) (containing ≥2, 300 mg sodium) and mean sodium content of purchases; changes were assessed by difference-in-difference regression models, adjusted for demographic and location co-variates. At both FSR and QSR, there was not a significant change in the proportion of NYC respondents purchasing 1 or more high-sodium items, relative to Yonkers (FSR difference-in-difference: -4.6%, p = 0.364; QSR difference-in-difference: -8.9%, p = 0.196). Among NYC FSR respondents, mean sodium content of purchases significantly declined compared to Yonkers (difference-in-difference: -524 mg, p = 0.012); no changes in mean sodium were observed among QSR participants (difference-in-difference: 258 mg, p = 0.185). Although there was a reduction in mean sodium content of purchases among NYC FSR patrons following sodium warning icon implementation, the mechanism behind the relatively larger NYC decline is unknown.