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.