Displaying calorie counts on menus does lead consumers to purchase items containing fewer calories, according to a study of Starbucks outlets. The research, conducted in America by Stanford School of Business, found that customers on average purchased 6% fewer calories but crucially the level of sales was broadly unaffected. Almost all of the effect of publishing calorie counts is on food items, with beverage sales largely unimpacted – calories for food fell 14% per transaction, while beverages were static. On average, it led customers to purchase an average of 232 calories per transaction rather than 247. However, for consumers who averaged more than 250 calories per transaction, their calories per purchase fell 26%. The findings were reached on the basis of comparing sales at Starbuck’s outlets in New York, where calorie posting has been mandatory since April, 2008 against those in Boston and Philadelphia, were it is not. The third component of the study was to look at behaviour before and after calorie-counting legislation came into force in Seattle in January 2009. The results of the study are described in the working paper “Calorie Posting in Chain Restaurants,” which can be downloaded at www.gsb.stanford.edu/news/StarbucksCaloriePostingStudy.pdf.