Katherine W. Bauer, Ph.D., of the Center for Obesity Research and Education at Temple University in Philadelphia, and colleagues evaluated the change in energy content of lunch and dinner menu offerings at eight of the leading fast-food restaurant chains in the U.S. between 1997 to 1998 and 2009 to 2010.

Over the 14-year study period, the researchers found that there was a 53% increase in the number of lunch/dinner menu items. Across the study period, the median energy content of all menu items remained relatively stable. Within specific food categories there was an increase in the median energy content of desserts and condiments, a decrease in the energy content of side dishes, and no change in the energy content of main dishes and drinks.

"Despite increasing pressure and legislation directed toward the fast-food industry to improve the healthfulness of their menus, as well as statements by the fast-food industry that indicate they are increasingly providing healthful food to consumers, overall the energy content of fast-food menu offerings has not decreased over the past 14 years at the leading fast-food chain restaurants examined in the current study," the authors write.