Tue April 23, 2013
When Cheeseburger = Walking, Will We Eat Less?
Nutrition labeling has been required on packaged food since 1990, and the new federal food safety law will require calorie counts to be posted for restaurant food — all in an effort to get the American public to eat healthier.
But most studies on calorie count labels show they don't do much to nudge people toward better food choices. If I want that oh-so-delicious Chunky Monkey ice cream, knowing that a half-cup serving delivers 300 calories and 18 grams of fat isn't going to stop me.
But what if I knew that it would take me an hour and 20 minutes of brisk walking to burn off those Chunky Monkey calories? Would I think twice?
Probably, says Ashlei James, a graduate student at Texas Christian University. She tested how much people ate when given menus with labels that stated how much brisk walking would be required to burn off the calories in a given food item. She compared that to menus with calorie counts, and those with no information, and tracked how much people ordered and ate.
The menus with and without calorie counts had no effect on how much the 300 participants, ages 18 to 30, ordered and ate. But the people who saw the walking times listed ordered fewer of the burgers, fries, chicken tenders, salad, dessert, sodas and water on the menu. They ordered less food, and ate less, too.
"Consumers should become more aware of how much exercise it takes to burn the calories from energy-dense foods," says Meena Shah, a professor of nutrition at TCU, and James' mentor. "Once people learn that it takes an hour or two to burn calories from one food item, they might think twice."
It would take a woman two hours of walking to burn off a double cheeseburger, the researchers said.
The research was presented in Boston at the Experimental Biology 2013 meeting, so it hasn't been published in a peer-reviewed journal. But other studies have also found a benefit from putting the amount of exercise needed to burn a food choice front and center.
In 2011, researchers at Johns Hopkins University found that, when they put labels on soft drinks stating that it would take 50 minutes of jogging to burn off that sugar, teenagers shopping in a corner market were more likely to avoid soda and buy water instead.
And TV chef Jamie Oliver made the point on his show Food Revolution by letting teenagers pick a snack — and then making them walk around a track until they burned off the calories. That approach squares with how the Hopkins researchers viewed their findings.
"Why is it that [listing] the minutes of jogging was most effective?" Sarah Bleich, an assistant professor at the Bloomberg School of Public Health at Johns Hopkins, told The Salt back in 2011. "My personal feeling is that jogging works because it's a negative thing."
The idea of matching up food intake with energy expenditure isn't new. The Internet abounds with calorie/exercise calculators (type in "exercise calorie calculator" to find them). And weight-loss programs like Weight Watchers build those calculators into their online tools.
Would knowing how much work it takes to burn off a food persuade you to order differently? Or walk more?