Items on the breakfast menu, including the calories, are posted at a McDonald's in New York. Restaurant and grocery chains scrambling to post calorie counts on their menus by spring have been peppering the FDA with queries.

NEW YORK — How might a bread basket for the table be counted under America’s new calorie posting rules? What about seasonal items, croutons for salads, or pizza that’s cut into squares?

Restaurant and grocery chains scrambling to post calorie counts on their menus by spring have peppered the Food and Drug Administration with queries that offer a window — often complex, occasionally comic — into the ingredient riddles they are trying to solve.