FDA provides additional information about requirements for dual column labeling, serving sizes on Nutrition Facts label.
The following quote is attributed to Claudine Kavanaugh, Ph.D., MPH, RD, Director of the Office of Nutrition and Food Labeling in the FDA's Center for Food Safety and Applied Nutrition:
"With the introduction of the new Nutrition Facts label, a variation that consumers are seeing is the dual column label for some foods that can reasonably be consumed in one meal or snack. This label has two columns, one for listing the nutritional facts related to a single serving and one listing the nutritional facts for the contents of the entire package.
"In the guidance we have issued, we are helping answer some of the questions most commonly asked by industry about dual column label and serving size issues, including when dual column labeling is required, the definition of a single-serving container, how to determine the number of servings in a food product, and how these labels should be formatted for some products that have limited space for nutrition labeling.
"The new Nutrition Facts label has updated serving sizes for many foods. We know that Americans are eating differently, and the amount of calories and nutrients on the label is required to reflect what people actually eat and drink – not a recommendation of what to eat or drink. The new label, including this dual column layout, will drive consumers' attention to the calories and Percent Daily Value of nutrients that they are actually consuming."