This is a topic I've discussed in my book The Fibro Hand. I am a firm believer in keeping a food journal after being diagnosed with Fibromyalgia because chemical and food allergies and sensitivities can reek havoc on you and cause flares.
After starting my journal for a week, I started to notice a sensitivity to sugar substitutes and MSG. After eliminating those from my diet, I felt better. I started small in the beginning by eliminating it for a week or two and then went back, but I consumed much less of it.
I'm sensitive to many, many things, but I've found that eating organic, chemical-free food is best for me. My flares are very few and far between now and I truly believe that eliminating the fake foods I consumed helped.
This radio program is a great show to listen to. It's very informative on food sensitivities and actually discusses a lot of what I've already said. I've never done an MRT. It was not even heard of when I was diagnosed. I took the time to figure out what I'm allergic to and it took a few months to really figure it out. But it can be accomplished, especially if MRT are out of the question for you personally.
Food Sensitivities: Is Your Food Making You Sick?