A study released on January 6 from researchers at the Stanford Graduate School of Business examined consumer behavior before and after calorie counts were posted on menus, finding that calorie postings led to a six percent reduction in calories per transaction in New York City in 2008. The study was based on transaction data provided by Starbucks. Researchers found that consumers’ buying habits can be influenced by visible calorie counts based on the following:   

• Calorie posting reduced calories per transaction from an average of 247 to 232 (6%).   
• Almost all of the effect was related to food purchases. Average calories from food per transaction fell by 14%, of which 10% was due to people buying fewer items and four percent was due to people buying lower-calorie food items.   
• For those consumers who averaged more than 250 calories per transaction, calories per transaction fell by 26%.
• The calorie reduction persisted for at least 10 months after calorie counts were first posted.

The study also found that  revenues were not affected by the calorie-posting requirement. In fact, for stores located within 50 meters of a competitor, the calorie-postings led to an increase in
revenue. The study can be viewed at www.stanford.edu/ ~pleslie/calories.pdf.

Opponents of calorie-posting laws argue that nutritional information is already available on restaurants’ Web sites or brochures. Also, other studies have indicated that calorie postings have no effect on customers’ calorie counts, and that factors such as convenience and cost are still the most influential factors in purchasing habits.

In related news, a January 25 study published in Pediatrics found that parents given menus with calorie information picked items with an average of 102 fewer calories for their children than did the parents whose menus didn’t have the calorie data. However, there was no difference between the two groups in the amounts of calories in items parents selected for themselves.

Published in WholeFoods Magazine, March 2010