(CBS News) Educating people on the number of calories they should eat may not help them make better choices.
A new study published July 18 in the American Journal of Public Health showed that providing people with calorie guidelines did not help them make better food choices, even when calorie counts for each item were available on the menu.
Several states and cities in the U.S. require that chain restaurants reveal calorie information for their items. Congress has already passed legislation to develop a national calorie labeling system in order to aid health care reform.
However, previous studies have shown that listing calories hasn't exactly helped Americans trim down their waistlines. It hasn't helped that fast food and restaurant food still remain calorie-laden. A 14-year study showed that fast food restaurants have only made minimal improvements to the nutritional value of their items, and 25 percent of Americans eat fast food two or more times a week.
"The general inability of calorie labeling to result in an overall reduction in the number of calories consumed has already been pretty widely shown," study author Julie Downs, an associate research professor of social and decision sciences in the Dietrich College of Humanities and Social Sciences at Carnegie Mellon University, said to HealthDay. "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."
To see if teaching people how many calories they should eat would help, 1,094 consumers aged 18 and older at two New York McDonald's locations were provided information on recommended calorie intake before they ordered. New York is one of the cities that requires caloric information about each item to be posted on menus.
A third of the customers were given a flyer that said women and men should limit their calorie consumption to 2,000 and 2,400 calories per day respectively; another third got a flyer saying a single meal should contain between 650 and 800 calories; and a third were not given any information at all.
After they ordered, researchers looked at the customers' food receipts and had them fill out a post-meal survey.
Women who ate lunch bought an average of 824 calories, while the men purchased a meal containing 890 calories on average. This meant that women consumed 27 percent more calories than recommended in one meal, and men ate 11 percent more than the guidelines recommended.
The researchers discovered that giving people calorie guidelines did not make a significant difference in how they read and used the calorie listings on menus. In fact, people who were given calorie guidelines ate 49 more calories on average than those who did not get guidelines at all.
Downs hypothesized that people might see an item -- like a Big Mac, which has 550 calories -- and think to themselves that it sounds reasonable and below their meal and daily calorie limit. However, they'll still order a side and a drink to go with the burger.
"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."
Studies have shown that if you want to slim down, you might want to avoid restaurants entirely. A May study in JAMA Internal Medicine revealed that a single meal from an independent or small chain restaurant contained on average 66 percent of an adult's estimated daily caloric intake. Another study on sit-down restaurants in the same issue revealed that a single meal contained about 56 percent of the daily recommended calories in a single meal.
On solution may be to tell people how much they have to work out to burn off their meal. Research presented at the Experimental Biology 2013 meeting in Boston suggested that listing how much exercise time instead of calories may work better. People who saw the time it would take to get rid of the calories tended to order 100 fewer calories than those who just saw the calorie counts.
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