"Your petition raises the question for the agency about whether 'whole grains' should be considered a food category, food ingredient, nutrient or something else," stated Margaret Glavin, FDA's associate commissioner for regulatory affairs, in her letter to Stuart Pape of General Mills.

General Mills recently switched to using 100 percent whole grain flour in all of its cereals. Bakery industry leaders were initially concerned that the petition would not consider the greater moisture content required for baked products as compared to cereal. The FDA said it recognizes the healthfulness of whole grain foods, but needs to continue reviewing how to define whole grain.

"Although FDA is denying your petition, the agency acknowledges the need for action on this topic. The recommendations from the recent Dietary Guidelines for Americans 2005 demonstrate the consumers can benefit form increased consumption of whole grains," the letter continued. The agency also advised that manufacturers may use factual statements on food labels, such as "10 grams of whole grains" and "100% whole grain oatmeal."