A spoonful of added sugar makes the medicine go down, but before consumers take a dose of indulgence in the future, bakers are likely going to have to list any extra sugar on the package. Americans on average get about 13% of their total calories from added sugars, with major sources being sugar-sweetened beverages and snacks and sweets, according to the Food and Drug Administration.

“It is difficult to meet nutrient needs while staying within calorie requirements if you consume more than 10% of your total daily calories from added sugars,” the F.D.A. said. “The updates to the label will help increase consumer awareness.”

The F.D.A. defines added sugars as those that are incorporated during the processing of foods or that are simply packaged such as a bag of table sugar or container of syrup. They include monosaccharides, disaccharides, sugars from syrup and honey, and sugars from concentrated fruit or vegetable juices.

The American Bakers Association questions the science behind the inclusion of added sugar on the label, said Lee Sanders, A.B.A.’s senior vice-president of government relations and public affairs and corporate secretary.

“There’s not an analytical method to measure for added sugar,” Ms. Sanders told Karlee Renkoski, associate editor, for the September issue of Baking & Snack. “In the baking process, sugar feeds the yeast, so what you put in is not necessarily reflected in the final product.”

Although the F.D.A. has included a formula for bakers, Ms. Sanders said it is several pages long and too complicated, so it would be helpful for the F.D.A. to provide more guidance for measuring purposes. In the end, listing added sugars will probably end up as an additional headache for many bakers.