If you want to avoid food additives, start with this list of additives to avoid.
The most accessible pages for reducing food chemicals are maintained by Sue and Howard Dengate at www.fedup.com.au. If you are just starting out, try the shopping list and the Information tab on their page.
The best reference with up-to-date lists of natural and artificial food chemicals in low, moderate, high and very high categories is found on the RPAH webpage.
For recipes, see the collection of links on the sidebar of my page.
And just in case all this talk of food chemicals is freaking you out, a reminder that all food is made of chemicals.