Food Chemistry Unit Plan Starter

This is a draft to an elementary Food Chemistry unit plan. It is not an all-in-one guide but a starting place with some ideas for phenomena, teacher background, and activities. The phenomenon could be used in middle school or high school as well.
Phenomena: The Jonas Brothers eat cupcakes to celebrate their best concert ever. Joe and Kevin feel fine and get a quick boost of energy from the sugar but then feel tired. Nick, however, gets no boost, and immediately feels more tired and sluggish. Why do you think Nick might have a different reaction to the nutrients in the cupcake than his brothers?
Alternate Phenomena: How do diet cola and regular cola affect our bodies differently?
Essential question: How do our bodies use nutrients for energy?