Here's a thought about fruit. I've read about the Feingold Diet for kids with Attention problems or behavior problems, and they eliminate food coloring (FD&C Dyes) and certain fruits from the diet. They say these foods contain natural substances that some people react to. It's not a true allergy, you don't break out in hives or have a breathing problem, but there is a definite reaction. So you might look into that. The Feingold Diet it's called.
Joanne