Researchers from Drexel University say including nutritional information on menus actually does lead diners to order food with fewer calories.
Since 2010, Philadelphia chain restaurants have been required to display nutritional information, including calorie counts, on menus. About 80 percent of the consumers Drexel and the city studied said they saw the labels -- and 26 percent said the information affected their choices at the sit-down restaurants.
People opted for healthier food, according to Dr. Giridhar Mallya of the city's Department of Public Health.
"So the meals had 150 fewer calories, 220 milligrams less sodium, 4 grams less saturated fat, and 15 grams less of carbohydrates," he explained.
Beth Leonberg, who directs a dietetics program at Drexel, said the menus are significantly affecting what people eat.
"The individuals who were dining at the restaurants that had labeling, overall chose to purchase about 150 fewer calories, about 225 milligrams less of sodium and 3.7 grams less of saturated fat, compared to individuals dining at the same restaurant chain," she said. "Outside the city of Philadelphia, where there was no menu labeling."
Many consumers who looked at the labels still purchased oversized, unhealthy meals.
This was the first large study done looking at the effects of menu labeling in sit-down restaurants, Mallya said.
Previous research had focused on fast-food chains.