(Undated)  --  Minnesota students may soon find candy bars replaced with granola bars in both in-school vending machines and at the lunch counter.  The U-S-D-A is proposing nutrition requirements along the lines of much-maligned changes to the school lunch program when it comes to snacks available in schools.  U-S-D-A Undersecretary Kevin Concannon (KAHN'-can-un) says the changes are part of the Healthy Hunger-Free Kids Act, and they are proposing changes that have been well researched.  The plan is to limit food in vending machines to under 200 calorie choices, which must also meet other nutritional guidelines when it comes to fat and sugar.