ATLANTA – While menu labeling has not yet affected the average nutritional content of fast-food menu items, it may motivate restaurants to increase the availability of healthier options, according to an exploratory study conducted by researchers at the Centers for Disease Control and Prevention.

The study examined seven years of nutritional data, from 2005 through 2011, from five chain restaurant companies operating in areas requiring nutrition labeling on menus (case restaurants) and four chain restaurant companies operating in areas that don’t require nutrition labeling (control restaurants).

To determine the presence of “healthier” options, the researchers used criteria based on Dietary Reference Values for a 2,000-calorie diet, the Food and Drug Administration standards for packaged food labels, and the Dietary Guidelines for Americans. Nutrient analysis was limited to calories, cholesterol, fiber, saturated fat and sodium.

Throughout the study period, the researchers found the nutritional profile of fast-food menu items across all restaurants showed high levels of sodium and saturated fat coupled with low levels of fiber. The proportion of healthier adult entrees that met four of the five nutritional guidelines remained less than 25 percent, with fiber and sodium least likely to meet healthier standards, the researchers said.

“Control restaurants had a lower proportion of healthier items than cases, remaining at approximately 7 percent over the study period,” the researchers noted. “In contrast, case restaurants increased the proportion of healthier entrees after labeling regulations: from 13% during years 2005 through 2008, up to 20 percent by 2011.”

The study also showed the prevalence of healthier side dishes was higher among case restaurants than controls (23 percent to 15 percent, respectively) and did not change over time. Like entrees, sodium levels in adult sides were least likely to meet the nutrition criteria.

Only one of the case restaurants offered children’s a la carte entrees that satisfied four or more of the nutritional criteria to be considered healthier options. Meanwhile, about 60 percent of case restaurants offered entrees that met three of the five criteria, while 10 percent of the controls met the requirements. Similar to adult menu items, fiber and sodium in children’s menu items were least likely to meet healthier criteria, the researchers noted.

“We found that after the implementation of menu labeling there was a statistically significant increase in the percentage of healthier adult entrees at restaurants in jurisdictions with menu-labeling laws compared with restaurants that were not in jurisdictions subject to labeling,” the researchers said. “Little improvement, however, was seen among children’s entrees during this period, and no significant changes in average nutritional values were seen among adult entrees and sides.

“Our results suggest menu labeling may provide fast-food restaurants with motivation to introduce healthier menu options; however, greater pressure may be necessary to generate overall average nutritional improvements.”