Earlier this month, a study examining fast-food consumers in poor NYC neighborhoods found that the city's law requiring chain restaurants to post calorie info might not be making a difference in what people order. Looking at customers' receipts, researchers found that many had actually ordered slightly more calories than the typical customer had before the law went into effect. But a more comprehensive study of the law, released today, tells a different story.

Researchers from the NYC Department of Health and Mental Hygiene surveyed more than 10,000 customers at 275 locations of 13 different fast-food and coffee chains throughout the city in the spring of 2007, and over 12,000 in 2009, nearly a year after the requirements began. They found that customers who used the calorie information purchased an average of 754 calories' worth of food at lunch in 2009, while those who didn't see or use the information bought 860 calories' worth of food. Those who saw and used the information consumed 152 fewer calories at hamburger chains, and 73 fewer calories at sandwich chains, compared with other diners.

The overall calories purchased decreased at nine chains between 2007 and 2009, including dropping significantly at McDonald's, Au Bon Pain, KFC and Starbucks. Calorie consumption only rose significantly at one chain, Subway, but the DOH blames that on a huge increase in customers purchasing 12-inch sandwiches rose from 28 percent to 73 percent during the study period. Subway's “$5 Foot-long” advertising campaign may have had an impact, too.