Menu labeling has made more people aware of how many calories are in restaurant meals and has some people reducing their intake, according to new research published in the American Journal of Preventive Medicine.

The study evaluated the effects of new requirements for chain restaurants to label their menu items with their corresponding by following restaurant patrons 18 months after implementation of the law—a longer period than previously published studies. The researchers looked at various types of chain restaurants, including burger restaurants, sandwich shops and .

"Most people have no idea how many are found in ," said lead study author James Krieger, M.D., M.P.H., of the public health department of Seattle and King County in Washington.

The study found that after the regulations were put in place, more people reported being aware of posted calorie information. After 18 months, customers of taco restaurants consumed fewer overall calories and customers of coffee establishments consumed fewer calories from beverages. Those results may be due to "customization," Krieger said—people can decide whether to put additional calories of sour cream or guacamole on a taco, for example. In coffee houses, customers choose the size and the for a drink.

"There was not much change seen among burger and sandwich restaurant patrons," he said. "Women purchased fewer calories than men as a result of menu labeling, particularly at coffee establishments."

Implications of these findings are broad, since 130 million people dine out daily in the U. S. and it's estimated that the average U.S. adult eats 4.8 meals per week in restaurants. Additionally, Krieger noted, nearly half of all food dollars are used to buy meals outside the home with a third of total calories consumed each day coming from out-of-home food.

It seems that a wide disconnect exists between perception and reality with regard to calorie counts, said Krieger. "The higher the actual calories, the bigger the difference between what people believe are the calories in a given menu item and the actual calories it contains. The bigger picture requires changing what people think is 'normal.'"

"The point here is that change takes time, but that small changes all add up," said Tracy Fox, M.P.H, R.D. of Food, Nutrition & Policy Consultants in Washington, D.C. "National menu labeling would be really helpful. We're still waiting for final rules to come out of FDA. Once more people see it in more places more frequently, it will become something they start to recognize and understand, to be able to put more in context. When awareness is higher, use of the information will be even greater. Efforts like menu labeling, along with improving food quality for school meals and getting junk foods out of school, will make it easier for people to make healthy choices wherever they are."

is but one piece of the complex obesity pie, said Krieger. "It's not the single intervention, but one of several intersecting, overlapping strategies that encourage us to eat healthier foods and be physically active."

More information: Kreiger, J. et al. (2013). Menu Labeling Regulations and Calories Purchased at Chain Restaurants, American Journal of Preventive Medicine.

Journal information: American Journal of Preventive Medicine