We eat whole unprocessed foods, but we don’t eat grains at all.
A good place to find a lot of information is MDC’s nutrition boards. Most people have a very difficult time properly digesting grains, and you can find more information about that in the sub-board Traditional Food.
A really good place to start is by eliminating foods that you know to be bad for you. Most people start with hydrogenated oils and HFCS (High Fructose Corn Syrup). Eliminating those two things plus a few others like MSG and Aspartame (NutraSweet) eliminates most processed foods.
Shop locally as much as possible… farmer’s markets, local farmsteads, small grocers (inquire as to where they get their produce). Buy produce in season, which right now pretty much limits you to apples, pears, citrus, lettuce, greens, mushrooms, and anything in the cabbage family (broccoli, cauliflower, brussels sprouts, etc.). Don’t buy food that has been imported from another Hemisphere (Chile is the big one around here).
If you have to buy something out of season, buy frozen first, canned next, fresh last. Read labels of anything canned, there will often be hidden ingredients like sugar in your veggies, and fruit is almost always packed in sugar. I do my best to only buy canned foods that contain a single ingredient plus usually salt and/or water (tomatoes, corn, green chiles, water chestnuts, coconut milk, etc.).
When you’re first starting out, menu planning can help a lot. If you have favorite dishes that you can make meet your criteria, it can really help your family in the transition. Plan out EVERY meal for a week (if you shop weekly)… breakfast, lunch, snacks, dinner and dessert. Planning it out will really help you to not get discouraged. After you’ve done that for 3 or 4 weeks, you’ll have a healthy selection of meals to choose from and a much better idea of how it all works.
If you’re planning on transitioning your family from something like white rice to brown rice (for instance), don’t buy 10 lbs of it. Buy enough for 1 meal and take it from there. You may have to try several different breeds or types before you find one your family can live with.
Buying in bulk can save you money, but be sure you understand how to properly store what you’re buying. A lot of organics can go bad quicker than non-organics. Potatoes for instance are sprayed to prevent sprouting, but if you’re buying organic potatoes, they haven’t been sprayed, so will sprout if not stored correctly (I have about 10 lbs of what are now seed potatoes).
Have a really solid idea of what you want to accomplish as you approach this. Do you want to eliminate processed grains? conventional produce? feed-lot beef? sugar? Having defined boundaries can really help in accomplishing those goals.
Ok, a bit rambling I suppose… hope some of it helps you.