It all goes back to the Food Guide Pyramid, the visual representation of the Dietary Guidelines for Americans that was created by the USDA in 1992. The Pyramid divides food into five groups--bread, vegetables, fruit, milk and meat, along with a section of sweets, fats and oils--and assigns each (except for the last) a numerical range of servings.
"A lot of people were confused by the serving sizes that came with the Food Guide Pyramid," says Catherine Tarone, a nutritionist with the USDA's Center for Nutrition Policy and Promotion. "They saw that a hamburger roll was two servings of bread and thought it meant they should only be eating half a roll."
The Pyramid recommends eating six to 11 servings of bread a day. A hamburger roll counts as two servings since it has roughly the same calories and nutrients as two one-ounce slices of bread, which is a standard serving from the bread group.
