I would find some taste you enjoy and work on flavoring and eating foods like that. Some kids get a fear of swallowing because of having to take nasty tasting medicine which is why mother's will crush a pill up in jam, etc. I'd try the same sort of thing; something easier to eat or that you enjoy, pair that with something a bit more difficult.

Start with something like Jello and then put some small pieces of fruit in the jello, (especially "easy" fruit like banana) etc. and work up to "harder" fruit or shift to quiche and put veggies in it, etc.