Tried once but my message doesn't appear, so here goes once more:
Not a lot of research has been done in this area; obviously as research costs money, most research done relates to things that will then rpove lucrative, ie medical therapies. I know of a few, where the particpating fibros were put on nearly raw vegan diets, excluding (among other things) MSG and aspartame. With good results.
That said, has to be taken into account that everyone is different, and especially so in the case of fibromyalgia - seems to me it's really about symptoms that can be caused by so varied things.
I have been vegan for years (not because of fibro or anything food/health related), and that might be one reason I never had it as bad as some people (I have constant pain, and sometimes really bad, but mobility is ok, never needed hospitalising etc). Last few years, I done quite a lot of modifications to my eating, with various results. I eat mainly raw, nearly no sugar (and try to limit foods that are 'naturally sugary', such as bananas and some other fruits), nearly no hydrogenated fats, nothing fried, plenty of veg (fresh and raw or steamed), little fat (and the fat I eat is usually not heated, and high in omega-3), no wheat and restricted amounts of soya.. and so on and so on. Pain levels really have gone down a lot, and it so worth it. But that alone has not been enough, I am still having pains and far more than tolerable. Yoga has been the other major contributing factor in getting better, I believe any dietary habits need to be accompanied by sound exercise and lifestyle habits (stress management, working habits and ergonomy etc.)
So anyway, most info around on food is what they like to call 'anecdotal', ie, people's personal stories. I think there's an important lesson to be learnt from it; we can learn from each others' experiences, and based on that do our own research (getting to know our bodies), but there's no cure-all cure-for-all.
So, here's the most common things I've heard from people to be problematic (and that are accepted among many health care professionals). Also, many fibro people have food allergies/sensitivities, so it's not clear exactly what teh issue is about always. Anyway:
Alcohol, MSG, artificial sweeteners (and other exitotoxins), chocolate, caffeine.
Dairy in all forms. Can only speak of what others have said.
NIghtshades (controversial if what really is at stake is the fact of them being nightshades, or if the problem is with some products that happen to belong to the family of nightshades, but being problematic for their type of starch - eg. potatoes) - ie potatoes, peppers, tomatoes, aubergine etc (there are lots)
Heavy meals and foods (high in fats, proteins, or especially, heavy combinations fo foods - fats WITH starch or the like)
Animal flesh. Don't know personally, as I don't eat that.
Anything wheat or gluten.
Sugar. This is really a problem for many. hard to quit; though even if you do, don't expect immediate cure.
Soya, corn and other common allergens.
Well, can't remember more now. HOpe this is of any use.
Oh and one more thing: when changing one's diet, it is really adviseable to do it gradually, so as not to relapse, and to keep up with it for several weeks/months at least, to really see whether there's any improvement.