Do you read the calorie count listed on a menu before ordering your lunch? And does it affect what you order?
Fast food restaurants around the country are poised to add calorie counts to their menus, thanks to a directive from the Affordable Care Act, and lawmakers and public health officials alike hope that you will consider calories at the counter.
Like much of the ACA, the emphasis is on prevention—in this case, in the fight against obesity. The policy, the details of which are currently being designed by the FDA, tackles one of our biggest obesogens: The food environment. But the reaction from public health officials has been mixed, due to some skepticism about the value of a calorie. Instead, a subset of researchers are asking: Is there a better way to measure what we eat?
The largest problem with menu calorie labels is simply that they may not be very effective. Most of the research shows that restaurant customers, both adults and children, do not order fewer calories at the cash register when they see calorie values, compared to viewing more traditional menus.
What's more, researchers who use eye scans to study retail behavior report that people look at nutrition labels less than they believe they do.
Earlier this month, two obesity researchers from Johns Hopkins who specialize in calorie information wrote about the limitations of menu labeling in the New England Journal of Medicine:
"If customers don't understand what 250 calories means or how those calories fit into their overall daily dietary requirements, posting that information on a menu may not be very useful. That difficulty may apply particularly to minority populations and those with low socioeconomic status, who are at highest risk for obesity and tend to have lower-than-average levels of nutritional literacy and numeracy."
Instead, they argue, why not try another measure, one easily understood by anyone who's taken gym class: Exercise equivalency.
One of the op-ed's writers, Sara Bleich, has spent several years studying how low-income teenagers, a particularly intractable group, react to calorie labels. The teens, like city kids everywhere, have traditionally gone to neighborhood bodegas and corner stores to buy after-school snacks. Bleich and her team decided to post signs in these stores that valued sugary drinks not by the calories they innately contained, but by the amount of exercise that would be required to burn off the caloric value of a drink. They found that the teens were far more likely to choose a low-calorie option if the drink's caloric value was described in terms of exercise. The exercise labels reduced calorie purchases by 40 percent.
"We make food decisions quickly," Bleich said in an interview with HuffPost Healthy Living. "And we make unhealthy food decisions even quicker because we're cognitively in a stressed state, which means we'll defer to what the palate wants: what is tasty."
What's more, other factors that may take precedence can distract from the calories once a customer gets up to the cash register: price, social expectations and advertising can all get in the way of calorie calculation—especially for people who are not used to prioritizing health when they order a meal.
But even for those who both want to make healthy choices and who are knowledgeable about nutrition, exercise equivalencies can work. In a preliminary study in North Carolina, nutrition researchers Sunaina Dowray and Anthony J. Viera simulated a restaurant scenario to test the ordering behavior of consumers if they were given a menu with calorie counts alone or calorie counts in combination with either "miles to walk" or "minutes to walk." They found that study participants ordered meals with about 200 fewer calories—regardless of their education level or how well they tested for mathematical literacy—if they were informed of how many miles they would have to walk to burn off the meal.
That might not sound like a significant distinction—after all, it's simply another way of describing value in terms of calories. But exercise equivalents appear to be easier for people to contextualize.
“Most people don’t understand what a daily caloric intake is,” explained Dowray in an interview. “You have to know the calories, then put it in context of your compounded intake—it can be hard to interpret. With physical activity, you have a clear idea of what the calories mean for you.”
And actually, calories in versus calories out can vary widely. In their book Why Calories Count, Malden Nesheim and Marion Nestle explain that the calorie number on a nutrition label describes the inherent energy value of a food, but not the value as it pertains to your consumption of it. In other words, the calorie transforms once it's consumed, based on a person's own metabolism, body composition and overall diet—and based on the materials that comprise the food.
"Foods are complicated mixtures: fiber makes a difference and form makes a difference,” Nestle explained to Mark Bittman during an interview for the New York Times.
Many foods may be incorrectly labeled in terms of calorie value because it changes based on the way food is prepared and its freshness, and simply because of reliance on poor calculation. Almonds, for example, may comprise just over 30 percent fewer calories than the USDA had previously measured. And some evidence suggests that gut bacteria consumes some of the caloric content of our food, Mother Jones reports.
So if it isn't always accurate and it's hard to understand, why do we use the calorie metric at all?
Consumer awareness of calories isn't really so old. Until the 1920s, calories were an industry measure, used in the scientific community, the government and among engineers to determine the effect of food on energy levels. It was a scientific metric—something that helped quantify the power (heat and energy) of steam engines and other machines, according to Nesheim and Nestle. Chemists also began to measure calories—first in plants, then livestock, and finally in humans.
The measure is often known as the "Atwater" calorie. In the 1880s, a chemist named Wilbur Olin Atwater began to consider the calorie output of laborers, in particular bricklayers and their nutritional needs as a result of that exertion. Books like the 1918 blockbuster Diet and Health with Key to the Calories, written by Los Angeles Times columnist Dr. Lulu Hunt Peters, were responsible for applying calories to weight loss.
And for overall weight loss among motivated individuals, calories are useful. "For most uses, I think they're good enough," Nesheim told MyHealthNewsDaily. But from a public health perspective, there may be more work to do.
"People are making decisions at point of purchase," Bleich says, "and they need more and better information."