If you click on where it says "disABILTIES" at the top of this page it will take you to the Index. One of the top items is the "disABILTIES FAQ" which will gives lots of useful information. Start at Post #3 and look in the "Diets" section. YOu will find a lot of basic information as well as useful links.
Or, if you want an easier route, click on the link in my signature.