New research suggests that junk food at schools is not causing students to gain weight.
A Pennsylvania State University study looked at students who went from fifth grade to eighth grade.
While there was a significant increase in the number of students exposed to junk food at middle school ... there was no increase in the percentage of students who were overweight or obese.
In fact, the number actually decreased.
Researchers say childhood obesity policies need to target eating habits at home.
Copyright 2012 KPHO. All rights reserved. CBS News contributed to this report.