What’s Really On Your Plate?

Nutrition label accuracy is under attack. Photo via Shutterstock.

Calorie counting, the cornerstone of diets everywhere, has long been considered the best way to control what you’re eating. But scientists are now saying nutrition labels may not be so reliable when it comes to accurately measuring the energy extracted from foods.

Rachel Carmody, a postdoc at Harvard studying food energy, was one of the organizers of a symposium held in Boston Feb. 18 at the American Association for the Advancement of Science‘s yearly conference. At the meeting, nutrition experts discussed the flaws of the calorie assignment system—like, as an NPR article reports, that the current method doesn’t recognize calories in fiber, meaning estimates for whole grain products are lower than they should be. The meeting also shed light on some amazing discoveries like: cooked food delivers more energy than raw food; that we don’t tend to absorb all the fat we could from nuts like almonds; and the fact that there is energy expenditure associated with actually eating and digesting food. All of this means the numbers on those handy little nutrition labels aren’t totally accurate.

A 2011 study from Tufts University that tested food from various restaurants for calorie content and compared that data against the eateries’ posted caloric information also found a high margin of error, sometimes by as many as 400 calories. Lorien Urban, a researcher involved in the study, says in an ABC News article:

“We found that 20 percent of the foods we tested had 100 calories or more over what was stated on the menu,” Lorien Urban, a postdoctoral associate in the energy metabolism lab at Tufts University and first author of the study, told ABC News. “We would consider that to be a considerable amount.”

Flawed or not, food labels probably aren’t going anywhere soon. As Carmody says in the NPR article:

“We’re not recommending that people not pay attention to food labels,” Carmody told The Salt. Instead, she hopes that people “realize that something that’s more highly processed is going to represent more calories than in a less-processed form.”

So what it all boils down to is use common sense. You may not know how many calories you’re eating exactly, but standard health wisdom—keep portion sizes small, eat plenty of produce, and steer away from ultra-processed foods—still applies. And until the USDA reexamines calorie assignment criteria, food labels are still your best bet for going into a meal at least semi-informed.