A.S.
Cook the way your grandma cooked - a protein, a simple starch (potato or brown rice) and a vegetable. Whole foods, whole foods, whole foods. Decline any foods with ingredients that you cannot pronounce and/or spell.
If you are trying to eliminate sugars, potatoes and rice will be out for awhile.
Personally I think the problem with sugars are the processed ones.
Check your library before you buy a bunch of cook books. That way you can "try it before you buy it." One that I like is "Special Diets for Special Kids" - it is oriented towards asd issues but it is wonderful for gluten and dairy free recipes. I also like a book called "The Kid-Friendly ADHD & Autism Cookbook."
I also try to avoid genetically modified food, and artificial dyes. Whenever possible I buy organic produce.
Walmart has started to carry some gluten free products. Perhaps ask the manager for a list or the area of the store where they are located.
Good luck and good health.