I have a few foodstuffs to which I have allergies. These include barley and its products, including most beer and whiskey. It also includes cantaloupe (sp?), and because of the vigor of the response to the latter, I avoid most melons. It's quite sad because I like both those products. *Sigh*.
Then, there's foodstuffs that I have something of a religious aversion. I don't eat ham, pork, or most other forms of pig product, with the only exception of bacon. I also don't eat catfish, though I do eat pretty much all shellfish, and swordfish as well. I'd call those culturally-mediated avoidances. Bacon was introduced to me as a youth, and never left my palette of foodstuffs. I also don't pay attention to the Jewish avoidance of the combination of milk and meat; a cheeseburger is a definite pleasure, not to mention steak smothered in blue cheese (yum!).
I don't tolerate eggs in practically any form. No omelettes, no quiches, no over-easys. This has been true for far over forty years, and I don't expect any change in the near future.
I don't like eating chicken that's pink in the center, but I also don't like eating chicken that's so dry that you need to drink four ounces of water to unstick it from the back of your throat, either. Perfectly cooked seems to be impossible, these days, at restaurants, so I tend to avoid ordering chicken at same.
I don't eat coconut. I think it's a texture thing. I love Thai soups with coconut milk, so I think it's just the solid matter, in its form, that bothers me on some level.
I gave up caffeine some time ago when I realized that it was giving me heartburn. I never took to coffee, and rarely drank tea, but I survived my internship on 2 1/2 liters of Coca-Cola daily; when I switched to ginger ale, I lost 17 pounds in two weeks. Now, I'm in the process of switching to water. I don't expect such a profound change.
Diet soft drinks taste odd to me, and I won't drink them. Give me diet water, anytime.
Outside of those constraints, I'm pretty open to tasting anything. Folks who come to the Carnivore's Feast can attest to that...