Impact on sales transactions and purchasing behavior of a menu labeling policy in King County

Introduction: One potential factor for the trend in rising obesity rates is an increase in people dining out without knowing the calorie content of foods sold in these establishments. In January 2009, King County Washington implemented a regulation requiring chain restaurants to provide nutrition information at the point of purchase. One concern is the potential negative impact on sales transactions. This study will quantify the impact of this regulation on transactions and purchasing behavior at one Mexican fast food chain with locations within and beyond King County. Methods: We use a difference-in-difference econometric approach that compares a) total transactions/month, b) total calories purchased/month and c) average calories purchased/transaction between 7 King County restaurants and 7 non-King County restaurants both before and after (up to 9 months) the legislation went into effect. The study had 80% power to detect 15% change in transactions or calories. Results: For this chain, preliminary analyses suggest little effect of the legislation on transactions or calories purchased. Trends in transactions, calories, and calories per transaction did not vary and are nearly identical for the King County and non-King County locations. We will also report any changes found in customer substitutions. Conclusions: Our study is one of the first to describe the impact of nutrition labels using restaurant data.These results suggest that menu labeling may have a limited impact on both transactions and calories consumed in this type of chain restaurant. Future research should include other restaurant concepts to determine if impact differs by establishment type.