WASHINGTON — With the growing issue of obesity and poor diets, steps are being made to address the concerns. Grocery retailers are required to list nutrition information labeling on products, but restaurants have not been subject to those same guidelines.

An attempt has been made to tackle the problem with a clause in the 2010 Patient Protection and Affordable Care Act stating that all chain restaurants with 20 or more locations must provide calorie information on its menu. The U.S. Food and Drug Administration is finalizing the implementation of listing other nutrients.

The law prompts the question whether caloric and other nutrient labeling at restaurants will actually spur customers to make healthier choices when eating out. Researchers at the U.S. Department of Agriculture’s Economic Research Service examined consumers’ use of nutrition labeling and explored whether it had a positive effect on the customer.

In the study conducted by the E.R.S. and published in the September issue of Amber Waves, consumers were asked about their awareness and use of nutrition information. The researchers used data from the 2007-08 and 2009-10 Flexible Consumer Behavior Survey module of the National Health and Nutrition Examination Survey to examine the demographic and health-related risks of those who eat out.

Three key questions were asked, with each relying on a “yes” answer to continue to the second question. Respondents were asked if they had eaten out in the past 12 months, then, if yes, were asked if they had seen the nutrition information on the menu, and then, if affirmative, were asked if the nutrition information affected their order.

Most people go out to eat, with 90% responding that they had gone out to fast food/pizza places and 88% said they had gone to a full-service restaurant. However, few saw nutrition information. Only 21% of fast-food customers and 17% of full-service restaurant customers saw the nutrition facts. Of those who saw the information, 42% of fast-food patrons and 55% of full service used the information. Of all of the respondents to the survey, only 8% reported that they had used the nutrition information provided on menus.

An F.C.B.S. follow-up phone call asked respondents whether, if more widely available, they would use nutrition information. The question was asked to those who said they had eaten at a restaurant in the past 12 months. Response options were “often,” “sometimes,” “rarely,” and “never.”

A person’s Healthy Eating Index (H.E.I.) score, measurement based on a person’s adherence to dietary recommendations in the Dietary Guidelines for Americans and scored on a scale of 0 to 100, had a strong correlation with their answers. Those who answered “often” had the highest average H.E.I. scores, with the scores progressively getting lower for those who answered “sometimes,” “rarely,” and “never.”

The Affordable Care Act assumes that people will use the nutrition information. But this assumption may be a blind spot if the goal is to help consumers make healthier choices across the board. The study found that those who use nutrition information have markedly better diets than those who do not. Similarly, those who are more aware of their food choices in regard to nutrition would be more willing to use the information if provided on menus. The implementation of the labeling law theoretically will benefit consumers aware of their food choices, the study said, but will do little to benefit consumers who do not have healthful diets. One of the concerns pointed out in the study is if the law is seen as a solution to the unhealthful food choices at restaurants, it will only create a greater disparity between healthy and unhealthy dieters.