Mandatory Menu Labeling in One Fast-Food Chain in King County, Washington

Background As part of a comprehensive effort to stem the rise in obesity, King County, Washington, enforced a mandatory menu-labeling regulation requiring all restaurant chains with 15 or more locations to disclose calorie information at the point of purchase beginning in January 2009. Purpose The purpose of this study is to quantify the impact of the King County regulation on transactions and purchasing behavior at one Mexican fast-food chain with locations within and adjacent to King County. Methods To examine the effect of the King County regulation, a difference-in-difference approach was used to compare total transactions and average calories per transaction between seven King County restaurants and seven control locations focusing on two time periods: one period immediately following the law until the posting of drive-through menu boards (January 2009 to July 2009) and a second period following the drive-through postings (August 2009 through January 2010). Analyses were conducted in 2010. Results No impact of the regulation on purchasing behavior was found. Trends in transactions and calories per transaction did not vary between control and intervention locations after the law was enacted. Conclusions In this setting, mandatory menu labeling did not promote healthier food-purchasing behavior.