Changing dynamics of purchasing high-sodium items at restaurant chains in New York

Changing dynamics of purchasing high-sodium items at restaurant chains in New York

In a recently published study medRxiv * Preprint Server, Researchers examined whether New York City (NYC) restaurants' implementation of sodium warning regulations changed consumer purchasing.

Lernen: Änderungen im Kaufverhalten der Verbraucher in New Yorker Restaurantketten nach der Einführung der Natrium-Warnsymbol-Regel, 2015-2017. Bildquelle: JeniFoto/Shutterstock

In 2016, a sodium warning rule was enforced in NYC, requiring chain restaurants (with ≥15 national locations) to display symbols denoting high sodium content (containing ≥2,300 mg sodium) for items on the menu and provide a statement mentioning potential health risks. Nutrient content warnings promote transparency about the contents of foods and can thereby help promote improved public health. Reducing dietary sodium intake has been linked to a lower risk of cardiovascular disease and high blood pressure.

About studying

In the present survey-based study, researchers assessed changes in consumer purchasing at quick-service restaurant (QSR) and full-service restaurant (FSR) chains in NYC and Yonkers (control) before and after enforcement of the sodium warning rule.

Between October 2015 and 2016 (baseline) and between April and June 2017 (subsequent high). Basic information obtained from Applebee's (FSR) has been excluded due to advanced enforcement of the sodium warning rule.

McDonald's (QSR) and Burger King (QSR) were excluded because negligible/no menu items were eligible for the sodium warning symbol. The study's key findings were the number of purchases of high-sodium items and the calorie and sodium content of the purchases. The interviewers conducted the surveys daily between 5:00 p.m. and 9:00 p.m. at FSR and on weekdays between 12:00 p.m. and 3:00 p.m. at QSR.

Adults who visited the selected locations received a $5 incentive to participate in the study. Items purchased for personal consumption and listed on the purchase receipt were included and their calorie and sodium content were obtained from the MenuStat database. Individuals without purchase receipts or missing nutritional information for their purchases were excluded from the analysis. Additionally, people whose purchases were not verifiable or people who only bought drinks were excluded. Purchases of items containing >12,000 mg sodium (extreme outliers) were also excluded. Regression modeling was used for the analysis.

Results

A total of 738 and 923 participants were evaluated in NYC FSR at baseline and follow-up, respectively. The corresponding counts for Yonkers FSR were 419 and 544, respectively. The baseline and follow-up participants numbers for NYC QSR were 341 and 379 people, respectively, and the corresponding numbers for Yonkers QSR were 317 and 331 participants, respectively.

A significant decrease was observed in the NYC FSR participant group in average purchases of high sodium items (baseline vs. follow-up values ​​were 0.8 vs. 0.7 items purchased/respondent) and in the proportion of participants who purchased ≥2 such items (15% vs. three percent). However, there was no statistically significant difference between baseline (67%) and follow-up (65%) in the proportions of participants who purchased ≥1 high sodium item. In the Yonkers FSR participant group, a significant decrease was observed in the proportion of individuals who purchased ≥2 such items at baseline compared to follow-up (6% versus 2%). However, average purchases of high sodium items by City of Yonkers FSR participants showed no difference at baseline compared to follow-up.

Likewise, the proportion of people who purchased ≥1 high sodium item did not change significantly (59% vs. 62%). For FSR, no significant changes were observed in average purchases of high sodium items or the proportion of participants purchasing ≥1 or ≥2 such items in NYC compared to Yonkers. Results were similar for NYC QSR participants.

In contrast, in the Yonkers QSR participant group, the proportion of individuals who purchased ≥1 high sodium item increased significantly from baseline (25%) to follow-up (37%). However, the average purchases of such items did not show any significant changes. At QSR, the team observed no difference in average purchases of high-sodium items or the proportion of participants who purchased ≥1 such item between the two cities. However, the average sodium content in purchased items decreased significantly between baseline and follow-up in Yonkers FSR (2696 mg vs. 2254 mg) and NYC FSR (3245 mg vs. 2279 mg).

The decline in NYC purchases was significantly higher than Yonkers purchases. Similar trends were noted for the average calorie content of purchased items, with reductions in NYC (baseline versus follow-up 1524 kcal versus 1055 kcal) and Yonkers (1259 kcal versus 1009 kcal). For Yonkers, the proportion of NYC participants who purchased ≥1 high sodium item was not significantly different at follow-up (difference-in-difference for FSR and QSR was -4.6% and -8.9%, respectively).

In the NYC FSR participant group, the average amount of sodium purchased was significantly reduced (-524 mg difference in difference); however, such significant changes were not observed in the QSR participants (258 mg difference in difference). At QSR, the average amount of sodium in items purchased did not differ significantly from baseline to follow-up in New York (1977 mg vs. 1777 mg) or Yonkers City (2193 mg vs. 1735 mg). Average calorie consumption decreased from baseline to follow-up in New York (946 kcal versus 794 kcal) and Yonkers City (1047 kcal versus 836 kcal).

Overall, study results showed that the decrease in the average amount of sodium purchased at NYC FSR following implementation of the sodium warning order was encouraging; however, a corresponding decrease in the proportion of people purchasing high-sodium items was not observed.

*Important NOTE

medRxiv publishes preliminary scientific reports that have not been peer-reviewed and therefore should not be considered conclusive, guide clinical practice/health-related behavior, or treated as established information.

Reference:

• Divya Prasadet al. (2022). Änderungen im Kaufverhalten der Verbraucher in New Yorker Restaurantketten nach der Einführung der Natrium-Warnsymbol-Regel, 2015-2017. medRxiv. doi: https://doi.org/10.1101/2022.08.22.22279098 https://www.medrxiv.org/content/10.1101/2022.08.22.22279098v1

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