Eating as healthily as possible is always a good idea. After all, the mind-body connection includes the physical! But you don't have to be perfect all day long - obsession and guilt over one's diet is never a good thing.
That said, for the vast majority of us on these forums, working on the management of our emotions and getting back to living without fear or obsession is the true answer. This is far more powerful than anything else we can do.
You'll see some people who "healed" after drastically changing their diets, only to feel sick again months or years later. Sometimes it's a placebo. Sometimes it's a temporary fix that relaxes the body for a little bit. But unless you have a vitamin deficiency or a true food sensitivity (and by "true sensitivity" I mean a sensitivity that is not caused by emotions, which certainly does happen), you don't need to get wrapped up in this and view it as your key to healing. It's not.
It's funny. In some of my posts from earlier this year, I wrote about how eating healthily "cured" some chronic withdrawal symptoms I was experiencing. I had read online that it would help, so of course it did. But the symptoms returned shortly after. An emotional process was making them stick around for me, and I needed to address that.
Sometimes I recommend natural supplements to people to calm their bodies down while they work on emotions, but nothing is more important than a life filled with love and happiness, and eliminating fear and obsession.
Long story short: people aren't truly being cured of fibro through their dietary choices. It's just more biological thinking. Focus on your emotions. Also, feeling guilty over eating a cupcake once a week because you think it'll aggravate fibro symptoms more is not good for anyone. Incorporate healthy food choices (along with some snacks to keep you sane) into your daily regimen because the body needs fuel, not because you think it's a cure for fibro.