All four of my Aunt's kids suffer from ADHD, and I realize that you're not talking about ADHD in your case but it has a link. One of her husbands (I think number 3) believed the story that red dye made the hyperactivity worse. So, they removed all red dye from the home - cereal, juice, kool-aid, jello, EVERYTHING (and after having a daughter allergic to red dye the list is extensive). The end result - there was very minimal change in their behavior. My guess would be, if there is red dye in the juice then it's not 100% juice (and in my world not juice, but a form of kool aid), but also if it's not 100% juice then it likely has added sugar versus natural sugar. That added sugar could be part of the problem. I know, again from experience, that 100% juices do not have artificial dies in them. I would recommend bringing along a 100% juice with you to those events - or deal with the hyperness. Our kids get hyper when they are either really tired or really excited about something, so it could be a response to that. Good luck!!