A study of sales at 222 Starbucks coffee shops in New York City has concluded that a law requiring clearer posting of the calorie content of food items has successfully, although not substantially, reduced customers’ overall calorie consumption.
The study, by researchers at Stanford University’s business school, is the most comprehensive yet on the impact of posting calorie counts on menu boards, required by law in New York city since April 2008.
It concludes that the average calories per transaction at Starbucks fell by 6 per cent, from 247 to 232 calories, which it conceded would in itself not be sufficient to have a substantial direct impact on growing obesity levels.
New York City was the first jurisdiction to adopt calorie posting measures that have been followed by similar laws in California, Maine and Massachusetts, and by proposed federal legislation.
The Stanford study tracked all sales receipts at the city’s Starbucks stores from January 2008, before the legislation was in force, until the end of February 2009. It also compared the New York data with sales at stores in Philadelphia and Boston, which did not have calorie counts on menu boards.
The study found that most of the reduction in average calories per transaction was related to food purchases, which fell by 14 per cent. It concluded that three-quarters of the reduction was due to customers buying fewer items, and one-quarter to them opting for lower-calorie items.
The researchers also analysed data from 2.7m anonymous Starbucks cardholders across the US, which provided further information on the varied responses of customers.
The card data showed that customers who averaged more than 250 calories per transaction prior to the calorie posting requirements reduced their average by 26 per cent – suggesting that the effect of calorie posting may be higher on consumers who are eating more than the average.
However, the researchers say that a 6 per cent reduction in calories, even if mirrored at other restaurants, will “not by themselves have a major impact on obesity”, given that typical weight loss programmes propose reductions of 500 to 1,000 calories per day.
But it concludes by arguing that the costs of menu posting are comparatively low, so that even small benefits could outweigh the costs.
“There may be public education benefits from the policy: consumers’ exposure to calorie information may make them generally more aware and attentive to the nutritional value of the foods they eat,” it says.
The restaurant industry initially opposed calorie posting legislation, but last June agreed to support the effort to pass federal law to create a national standard.
A Starbucks spokesman said that the study had “showed us first-hand that menu labeling can work to help consumers make choices”, while adding that Starbucks believed any standards established at a national or global level should be uniform.