US: Calorie labeling and lunchtime purchases
Title: Changes in energy content of lunchtime purchases from fast food restaurants after introduction of calorie labeling: cross sectional customer surveys
Authors: T Dumanovsky, C Huang, C Nonas, T Matte, et al
Reference: BMJ 2011; 343 (open access)
Reviewer: Joaquin Barnoya, MD, MPH, Contributing Editor, ProCor; Research Assistant, Professor of Surgery, Washington University in St. Louis, Missouri, USA; Director, Research and Education, Unidad de Cirugia Cardiovascular de Guatemala, Guatemala
Reviewer comments: As the obesity epidemic spreads worldwide, population based-strategies will be part of the solution. Calorie labeling might be one such strategy. Even though labeling was found successful in this study, it is worth highlighting that women and those in affluent neighborhoods were more likely to use calorie information. Therefore the question remains, for poor neighborhoods (that happen to have the highest prevalence of obesity) what is the best strategy to improve consumption patterns? Is labeling the answer?
Purpose of study: To assess changes in lunchtime purchases at fast food chains in New York City since the implementation of the city's calorie labeling regulation
Location of study: New York City, New York, US
Methods: Three hundred store locations were randomly selected from a sampling frame of 1625 stores. After exclusions, 275 locations were visited in 2007 and again in 2009. At follow-up, 22 locations had closed or did not allow data collection (these were replaced with restaurants of the same chain in the same or adjacent zip code). Given that customer volume varies greatly, authors set target for data collection at 55 customers or two hours for each location. Field workers were stationed in front of the locations during weekdays, for 12pm-2pm at fast food chains and 2pm-4pm at the two coffee chains. Adult customers were approached as they entered the restaurant and asked to provide their register receipts when exiting and to complete a brief survey. All were asked if they saw calorie information in the restaurant and, if so, whether the information influenced their purchase. Each item purchased was entered as it appeared on the customer's receipt. Authors used the calorie information posted on the websites of each restaurant chain at March 2007 and March 2009 to ascribe a value to each item. Two outcomes were assessed: change in mean energy content (kcal) per purchase before and after regulation, and mean energy content (kcal) purchased among customers who said that they used the calorie information when deciding to order.
Results: Register receipts and surveys were collected from a total of 7750 customers in 2007 and 8730 in 2009 at 168 fast food chain locations. Of customers that were approached, 60% agreed to the study. In 2007 only the Subway sandwich chain provided calorie information. In 2009, all chain included in the study were compliant with the new regulation. Sample distributions by fast food chain were similar for the two time periods. A third of receipts came from stores in high poverty neighborhoods. Fifteen percent of customers reported using the calorie information when deciding on their purchase. Women (18%) were significantly more likely to report using calorie information than men (13%) as were customers in the wealthiest (19%) neighborhoods compared to those in the moderate (17%) and poorest (12%) neighborhoods. Customers who reported using calorie information also purchased fewer food items on average and fewer purchased beverages. After regulation, three major chains with large sample sizes showed statistically significant reductions in mean energy content per purchase: 44 kcal reduction at McDonald's, 80 kcal at Au Bon Pain, and 59 kcal at KFC. Customers who reported using the calorie information after regulation purchased 106 fewer calories, on average, compared to those who didn't see or use the information. After adjustments, the new regulation led to a decrease in 20 kcal in mean energy content per lunchtime purchase (p=0.001). Those using the calorie information after regulation reported 75 fewer kcal than those who did not.