I'm now a bit cautious about thinking I can change me head by changing my diet. In psychology there's always been a brain/mind split. The brain path is to treat your "disorder" as primarily a chemical process. This leads you to pharmaceuticals. But it can also lead you to better nutriton, exercise, fresh-air-and-sunshine, etc...
The "mind" side is what traditional psychology has been about -- talk therapy, reflection, etc..
Right now, the "brain" side has taken the lead. We've all heard the Woody Allen jokes about being in psychotherapy for years and getting nowhere. And the science of the brain has advanced a lot.
But, IMO, it's a mistake to dismiss the "mind" side. The brain side means you don't have to deal with painful stuff. But I think it's dealing with that stuff that provides the biggest breakthrough. Right now I'm reading several Jungian books aimed at men. And they're eye-opening. I'm seeing a shrink and journaling. In the journals, I'm writing down select incidents from my life that carry shame and guilt. It's not fun. But it's cathartic. Nobody will see these, probably not even my shrink. But it's liberating.
I'm an atheist but I've come to realize that our modern culture's determinist view of humanity has taken us on a wrong turn. Rational choice theory, selfish genes, etc.. are ridiculously reductionist. Your brain's more than chemicals. Citizens are more than consumers. You are more than your genes.