Have you ever bought a snack from a vending machine, glanced at the label, and then eaten the whole package only to discover later that you actually ate two servings — double the calories, double the fat, and double the sodium? If so, you’re not the only one.

The current Nutrition Facts label is 20 years old. It provides consumers with information about the serving size, number of servings, calories per serving, and the amount of certain nutrients per serving in packaged foods. However, consumers often miscalculate or overlook the number of calories, grams of fat, and other nutrition information on food labels in which there are two or more servings in a package.

The researchers found that two labeling changes could make nutrition information on packaged foods easier to understand.

Researchers with the FDA’s Center for Food Safety and Applied Nutrition set up an online survey to assess consumers’ accuracy in using different versions of the Nutrition Facts label as well as their perceptions of how useful, trustworthy, and helpful the labels were. More than 9,000 people participated in the study.

The FDA commissioned the study to look at whether presenting the serving size and nutrition information on the Nutrition Facts label differently might help consumers. They were especially interested in products like chips that are usually consumed in one sitting, but which often have nutrition information based on two servings per container, leading people to miss the fact that they are getting twice the calories and fat they see on the label.

Participants in the study were given Nutrition Facts labels in nine formats plus the current label format for four fictional foods — two frozen meals and two bags of chips. Three groups of labels were used including a single-column format which showed nutrition information for products with two servings per package, a two-column format which displayed nutrition information for products with two servings per container, and a single-column display that listed the food as a single, large serving.

The researchers found that two labeling changes could make nutrition information on packaged foods easier to understand: 1) using two columns of information, one that details nutrition information for a single serving and one for the entire package; and 2) listing nutritional information for the whole package. Both formats helped people more accurately determine the number of calories and the amount of fat or other nutrients per servings as well as in the whole package.

"This research is just one step in understanding how some potential food label modifications might help consumers make better decisions. Ideally, we would like to see how these labels perform in a more realistic setting, such as in a grocery store, with actual packaged foods as opposed to large labels on a computer screen," said researcher Serena C. Lo of the FDA in a press release. "The Nutrition Facts label is only one tool that can help consumers make informed food choices and maintain healthy dietary practices, but it is a valuable tool so it's important to continue exploring ways to support effective use of the label for these purposes."

The study is published in the Journal of the Academy of Nutrition and Dietetics.