Doge, you are probably right that more veggies would be good (and not mentioned in the OP's post), and that kids can overdo sugar and then crash later. But it sounds like this is the 11 year old's first race, and my point was to eat what you usually do and don't worry about it. Having the gu or race drink would help the kid feel like they are doing something special to help them go fast and might be a psychological boost.