NEW YORK - According to a study that challenges plans to implement menu labeling nationwide, menu labeling at Taco Time restaurants in Seattle failed to produce measurable changes in customers' eating habits, Bloomberg reports.

More than a year after a local menu labeling law took effect, total sales and average calories per transaction in Taco Time restaurants in King County, Washington were identical to those at restaurants where menu labeling was absent, researchers from the Duke-National University of Singapore Graduate Medical School reported.

The findings reaffirm the results of a similar study in New York and cast doubt on whether menu labeling, part of President Obama's health-care reform laws, will effectively address the U.S. obesity epidemic, according to Eric Finkelstein, associate professor of health services at Duke-NUS who led the study.

"Menu labeling may have a limited impact on both transactions and calories consumed in this type of chain restaurant where menus already highlight health items," Finkelstein and colleagues wrote.

The King County law took effect in January 2009 and requires restaurant chains with at least 15 outlets and $1 million or more in annual sales to disclose calorie counts, as well as saturated fat, carbohydrate, and sodium content, for all food and drink at the point of purchase.

The King County study surveyed sales data from seven Taco Time restaurants in King County and seven in surrounding cities from January 2008 to January 2010.

Taco Time was the only chain approached by the researchers that allowed access to sales data, Finkelstein said.