Elementary school students will eat more whole grains when healthier bread products are gradually introduced into their school lunches, a new University of Minnesota study shows.

Whole grain breads are strongly recommended as part of a healthy diet, but children and pre-teens won't always eat them. For this study, researchers from the university's department of food science and nutrition monitored how much bread students threw away, and whether that amount increased as the percentage of whole-grain flour in the bread and rolls was gradually increased.

The study included meals fed to kindergartners through sixth-graders at two Hopkins, Minn., elementary schools over the course of a school year. Red and white whole-grain flour was added incrementally to products, but students showed no strong preference for either type of flour. Students didn't throw away more bread products until the percentage of whole-grain flour in the bread and rolls reached about 70 percent.

The research is important because it shows that a gradual approach to improving children's overall diets can be successful both for parents and school food-service workers, said Len Marquart, one of the study's authors and an associate professor at the university.