To work out food intolerance you really need to do a strict elimination program and do it properly. You can't do things one at at time or without professional guidance there are too many foods with multiple chemicals. We do the Royal Prince Alfred Hospital diet, which is an Australian model, they publish a fantastic handbook and a cookbook too, and then we had a local dietician to help us get started and to help make sense of our results along the way. Now it's a life style and nothing much has changed in a really long time.
You can google for the RPAH elimination diet handbook and I think they have the whole introduction online so you can read it. But their site is broken at the moment so I can't provide a link, presumably it will be fixed soon though.
Sue Dengate's books (for example Fed Up with Food) are very similar, though I am not sure if they are as strict, but they may be easier for you to get in the USA. Or maybe there is some local equivalent of our hospital based program.
My personal advice is also that if you are going to do it particularly for ADHD, go all out and eliminate dairy and gluten from the start (these would then be the first two you try to get back). Gluten, Dairy and Salicylate seem to be the most likely culprits. From the children I personally know who the diet helps, all of them have a problem with at least one of Dairy and Gluten, most have lost at least one of Amine or Salicylate, and all are preservative, flavour and other "number" free. But all of them have different sets of what they can and can't have.
I have to say though that I think the biggest impact from diet is on the hyperactivity/behaviour, which certainly makes your child easier to live with and less likely to get into trouble at school. However, I am not convinced it's done much for either of my children's inattentiveness and from what I understand research shows that this is the part of ADHD that is most harmful to a child's success academically (and presumably at work).
Last edited by MumOfThree; 03/22/13 11:14 PM.
