PITTSBURGH - Too much information might not translate into a low-calorie lunch.
A Carnegie Mellon University study reveals that while people benefit from the calorie listings on McDonald's menu items, providing them with recommended daily and mealtime calorie allowances had an unexpected result.
It appeared "to promote a slight increase in calorie intake," the report says.
The study of 1,121 adults who provided receipts and completed surveys upon exiting McDonald's locations in Manhattan and Brooklyn, N.Y., was published online July 18 in the American Journal of Public Health. Julie Downs, associate research professor of social and decision sciences at CMU, led the study.
"Most people are not going in and doing very specific math to figure out how many calories for each meal they should have," she said. They are focusing on the entree only or deciding if they eat more now, they will eat less later.
It was thought that more information would lead to fewer calories and better food choices in the battle against obesity. The study also highlights the difficulty in providing effective tools to persuade people to cut calories and lose weight in a nation where more than a third of the population is obese and more than another third is overweight.
"Restaurant meals are a natural target for policy interventions aimed at containing obesity," the study says. "They have accounted for a growing fraction of calorie intake over time, and at the individual level, obesity is positively associated specifically with patronage of fast-food restaurants."
Restaurants such as McDonald's "are especially popular with low-income individuals, who have a higher risk of obesity, and encourage additional calorie consumption by promoting larger meals" at minimal additional cost. Last September, McDonald's announced it would provide calorie totals on its menus.
With a Big Mac having 550 calories, and a recommended lunchtime calorie intake of 650 for women and 800 for men, the person might buy the sandwich and think there's wiggle room to add fries and a sugary beverage. But fries add 230 calories and the drink adds another 170, for a total intake of 950 calories, which far outstrips recommendations for either gender. One third of study participants with access to the recommendations purchased lunches exceeding 1,000 calories.
Recommendations, the study said, "can provide a false sense of staying within the calorie allowance, which could license larger purchases and allow consumers to ignore the calorie load of other components of the meal."
Providing incentives for people to choose healthier menu items could help, such as providing a discount for a combo meal that includes water or a diet drink, the study says. Calorie listings alone do benefit people interested in weight control.