ORONO, Maine, Aug. 31 -- University of Maine issued the following news release:

At lunchtime in rural Maine middle schools, University of Maine researchers stood at two points in the cafeteria.

At the first, students received a numbered card after picking up their meals. Researchers photographed each tray from above.

Then they waited.

Before students dumped what was left into the trash, researchers photographed the trays again.

The images captured a problem that plays out every day in school cafeterias: Students were offered fruit, but much of it was never eaten.

Sometimes they did not take it. Sometimes an apple came back with one bite missing. Other fruit was barely touched.

For UMaine researchers, those trays became the starting p...