Most people have heard stories about what can happen to someone not used to eating whole wheat who suddenly begins eating it a lot--and none of them are pleasant. The other day I was reminded of this by a guest we had in our home. I had made a simple meal of vegetable turkey soup (with real turkey broth from a bone I simmered), and cornbread from scratch (of course). Our guest gave many compliments on the meal and kept telling me how it really "hit the spot," and helped himself to seconds. But only an hour later he had to spend about 15 minutes in the bathroom. I have never had anyone's body react that way to my cooking, so it was quite baffling. Our guest said he knew for sure my food was all natural because normally when he eats things like that it takes a day or two to "go through." Well, this only added to my bafflement! And my pervading feelings were incredulity and pity, that he--that anyone--should be so accustomed to "fake," processed food that their bodies don't know how to handle the real thing. And yet, I'm sure many typical Americans are in the same boat--sadly.
My uncomplaining husband knows all about this, firsthand, as he had a crash course on home cooking and whole wheat when he married me. Now he would never go back, but it did take his body a while to adjust. Ideally, this adjustment should take place in a gradual, calculated way, with a goal in mind. Here is an excellent website to give you ideas on how to do that (scroll down about halfway). Basically, you need to identify the snacks, bread, pasta, rice, etc in your current diet that contains white flour and gradually replace them with those same items made from whole wheat flour. I didn't used to be so fond of wheat pasta, but I helped my family make that gradual change and now don't mind it at all, especially since it stretches farther by filling us up faster (and sticking). As we still have a good supply of white rice, I haven't yet completely made the switch to brown rice, but I plan to. All of us have improvements we can make.