Making general calorie consumption guidelines available to patrons of restaurants where calorie count labels are already on the menu does not lead to better food choices, new research cautions.
"The general inability of calorie labelling to result in an overall reduction in the number of calories consumed has already been pretty widely shown," said study lead author Julie Downs. "So that's nothing new. But in the face of that, there has been the growing thought that perhaps the problem is that people don't know how to use the information without some framework, some guidance," she explained.
"So what we tested is whether we could improve food purchasing behaviour by offering people general daily or per-meal calorie guidelines alongside food labelling in restaurants. But we found it didn't help at all," she said.
Downs, an associate research professor of social and decision sciences in the Dietrich College of Humanities and Social Sciences at Carnegie Mellon University, and colleagues report their findings in the July 18 online edition of the American Journal of Public Health.
In recent years various cities and counties including New York City, Philadelphia, San Francisco and King County, Wash. have mandated calorie-posting on chain restaurant menus, as have entire states such as California and Oregon, according to the study. Going forward, some form of national calorie labelling is set to kick in as part of the unfurling federal health care reform already passed by Congress.
Against that backdrop, for four months in 2008, the authors set out to provide standardised calorie recommendation information to more than 1 100 consumers aged 18 and up just before they purchased food at one of two NYC-based McDonald's restaurants, one in Manhattan and one in Brooklyn.
The information offered was gleaned from calorie policy set by the US Department of Agriculture and the National School Lunch Act. Half of the study took place just before the city implemented standardized calorie labelling on restaurant menus, half after.
Participating consumers were randomly given either: material recommending a total daily consumption of 2 000 calories for women and 2 400 calories for men; material apprising them that a single meal should contain between 650 and 800 calories; or no information at all.
The result: An analysis of food receipts and post-meal surveys revealed that calorie guidance did not seem to help consumers better interpret or make overall better use of calorie labelling when it was present. Moreover, guidance failed to prompt a drop in the total number of calories informed patrons purchased.
Instead, those who received overall caloric information chose to eat slightly more calories, not fewer.
"It's just speculation," Downs said, "but I think what is going on is that people see the daily or per-meal calorie recommendations." She gave the example of a Big Mac, listed at 550 calories. "Which is actually not unreasonable. So then [customers] maybe feel OK to go ahead and get a slightly bigger main dish, but at the same time still get the same side dish and drink they would normally get. And then all of a sudden they're up over 1 100 calories for the meal. Each one item may seem OK, but it adds up," she noted.
"In the end the bigger issue is that asking people to do math three times a day every day of their lives is a lot," Downs added. "Because it's not like we make a decision about what to eat just once. It's a lot of decisions. And if you add a cognitive (mental) burden on top of that it's a lot to ask."
For her part, Lona Sandon, a registered dietitian and assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, suggested that providing caloric information should be viewed as an important step towards building awareness, even if it doesn't immediately lead to better food choices.
"This continues to prove what those of us who work in the area of promoting healthy diets and lifestyles have known for years," Sandon said. "That is, knowledge does not equal or guarantee a change in behaviour. Knowledge is just one piece of the puzzle. We must consider people's attitudes, beliefs and values surrounding healthier eating and body weight," she pointed out.
"The pros of choosing fewer calories must outweigh the cons," Sandon added. "In other words, they must see a benefit that is strong enough to outweigh the cons of a high-calorie meal that will be immediately satisfying and tasty," given, she said, that the number one reason people say they eat is for taste, not health.
Study author Downs said, "Now there is a reasonable argument to make that we should have these calorie labels and access to information. Certainly, for someone who's already health conscious, providing information and transparency is helpful. But the problem comes when we think that this is the solution to the obesity epidemic among the at-risk population we're trying to address."
For more on food consumption guidelines, visit the U.S. Department of Agriculture.