I have read the responses so far and want to add the following about the Feingold Diet.
While it is congenial to think there are things we might do to remove the AD/HD, the fact is that since Feingold's research, AD/HD has been shown incontrovertibly to be a real, actual difference in how the brain is structured and how it uses essential brain chemicals.
Now, this doesn't mean that for any child, too much sugar, or carbohydrates, or bacon-lettuce-and-mayonnaise sandwiches, or just about anything, isn't a good idea. And, an excellent diet is imperative for any person coping daily with what amounts to chronic stress (listen, parents).
The Feingold Diet is exceedingly rigid and emphasizes the prohibition of certain foods and food substances, and we have learned a great deal since then about what foods build health. Studies that were done in an attempt to replicate Feingold's findings were inconclusive, but one thing stood out on most of them (and I apologize for not having the citation).
There were two variables most responsible for the reduction in "symptoms" and inappropriate behaviors: the increased domestic structure required in order to follow the diet, and the increased amount of attention paid to the children.