It may be a phobia, but I would still blame the parents.... there must have been a day somewhere, when suddenly the girl, in toddlerhood perhaps, had a massive tantrum, said all she wanted was a marsbar, parents could not calm her down, understandably gave in- that once.
Then, next day, same hting. Just want smarties. Parents gave in..... and it took years before alarm bells started going off, and they realised it had just gone too far, and now the poor girl has a MASSIVE hangup, where anything else causes all sorts of physical and psychological 'trauma'.
My sister is an unbelievably fussy eater. She's now in her mid 20's. It's all in her mind. She knows this, and is trying slowly, slowly, painstakingly slowly, to 'teach' her mind/body to like and accept foods. Sure, maybe it is a phobia, but had it been dealt with effectively when she was small, the problem would not have escalated so far as to become almost untreatable. It will take years to 'wean' my sister onto all manner of vegetables, and meats, well, most things.
She is the most stubborn and strong-willed person I know, was a toddler/child. I believe it was definitely a control thing in the beginning, as a toddler demanding more attention, but now it's gone beyond.
My parents are lovely, wonderful people, brought us up wonderfully, but it is kind of their fault it went as far as it did with my sister.