Ice cream. Assuming that you mean I have to decide between giving up ice cream forever versus giving up beer forever, but with the rest of my diet remaining unaffected, I would give up beer. I like ice cream more. Though not much more.
If you mean that I'm only allowed to consume all ice cream or all beer then I also choose ice cream. Both options would likely lead to my imminent death, but ice cream would be slower and I might survive if I was allowed to have all ranges of exotic favors. This ice cream has steak in it and green beans!