New York City's requirement that fast-food restaurants post calorie counts on menus led one in six customers to notice the information and buy foods with fewer calories, according to new research released on Tuesday.
While overall calorie consumption for the thousands of people tracked did not change, customers of McDonald's, Au Bon Pain and Yum Brands Inc's KFC were shown to make significant modifications, according to the study funded by the city of New York and the Robert Wood Johnson Foundation.
The report, published in the British Medical Journal, is one of the first to show a 2008 New York City law, requiring restaurant chains to prominently post calorie information, changed customer buying habits.
Advocates of the law see it as an important measure to help Americans lose weight, as more than two-thirds of the country's citizens are overweight or obese, conditions linked to health problems like high blood pressure and diabetes.
"We think, overall, these initial findings are positive," Dr. Lynn Silver, director of New York City's Office of Science and Policy and co-author of the report, told Reuters.
"We're optimistic, as calorie labels go national, and consumers become accustomed to using the information that chains will have a strong incentive to offer lower calorie options," she said.
Restaurant chains have begun to include lighter fare on their menus to help customers cut down on fat, sugar and sodium intake. The report cited examples at sandwich chain Cosi, which began using low-fat mayonnaise in its sauces, while coffee chain Starbucks made low-fat milk as its default and Applebee's introduced a menu with dishes under 550 calories.
All of these changes came after the New York calorie label law came into effect, the study said.
Separately on Tuesday, McDonald's said it will soon cut the french fry servings in its children's Happy Meals by more than half and add apple slices to every meal.
The New York city report surveyed the lunchtime crowd at 11 fast-food restaurant chains, looking at receipts for more than 7,300 people 12 months before the law took effect and for nearly 8,500 customers nine months after it was implemented.
For the three main restaurant chains studied, customers on average bought 44 fewer calories at McDonald's, 80 fewer calories at Au Bon Pain and 59 fewer calories at KFC.
Subway, the popular sandwich chain, saw a significant increase during the survey because of its promotional offer for a $5, foot-long sandwich. The other chains saw little change in their customers' purchases.
Earlier this year, a study published in the International Journal of Obesity, found New York City's label law had little affect on the food children chose to order.
While both studies focus on New York City's 2008 law, people across the country are keeping a close eye on the results.
President Barack Obama's 2010 healthcare overhaul mandates a similar requirement nationwide in an effort to curb the U.S. obesity epidemic.
In 2009, the Centers for Disease Control and Prevention estimated that at least 20 percent of adults in all states, except Colorado, were obese. The CDC also said medical costs related to obesity were estimated to be as high as $147 billion in 2008.