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

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. Consumer purchases, using receipts for verification, were assessed at 2 full-service (FSR) and 2 quick-service (QSR) chain restaurants in NYC and Yonkers, NY, which did not have sodium menu labeling, in 2015 (baseline) and 2017 (follow-up). Difference-in-difference regression models, adjusted for demographic and location co-variates, tested whether the proportion of NYC respondents purchasing high-sodium item(s) (containing [≥]2,300 mg sodium) or whether mean sodium content of purchases changed, in FSR or QSR. Relative to Yonkers, the proportion of NYC respondents purchasing 1 or more high-sodium items did not significantly differ from baseline to follow-up at FSR (difference-in-difference: -4.6%, p=0.364) or QSR (difference-in-difference: -8.9%, p=0.196). Among NYC FSR respondents, mean sodium purchased 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). While the reduction in mean sodium purchased among NYC FSR patrons after the sodium warning implementation is encouraging, there was not a corresponding reduction in the proportion of respondents purchasing high-sodium items. Further research that evaluates longer-term changes in the restaurant environment, including menu offerings and consumer purchases, following such policies is warranted.