Originally Posted by MV:
Try taking out all red dyes (cereal, candy, cookies etc that have it) and no processed food (microwave meals, fast food etc). It helped my DD tremendously and she has ADHD. We have the diagnosis and she's medicated but by changing her meals we were able to drop one of hers meds because it helped that much. Maybe it'll work for you. 
I agree with this route to take first, Silver! My dd is over 2 years since we took all the chemical stuff out of her diet. The reaction is immediate and noticeable when she eats anything with red or yellow dye (14 and 16 are the worst), nitrates, artificial flavors, colors, preservatives and she can't handle white flour at all for some reason. Everything I bake has whole wheat or another whole grain in it and she's fine. Throw a little white flour in there and we have a winner for beating a train in a race, both on foot and talking. lol
Also, early bedtime and plenty of outdoor time especially at key moments. DD has piano on Tuesdays and if it's bad weather and she doesn't play outside on Tuesday pm we HAVE to walk to lessons or she HAS to run/bike/rollerblade for 20 minutes beforehand or she CAN'T learn. I've learned over the years that it's important for me to provide the environmental changes she needs to function.
The only packaged stuff we eat is things that we understand every ingredient on the label and I could recreate at home.