Yes. As long as you know what each ingredient means and you know they are all kosher, you are fine. Though as usual, ask a rav before listening to some anonymous blogger.
(By the way, did your Big Gulp have a hechsher on it?)
There is no reason to assume that there is a problem. There are a few halachic arguments one can make to that effect, but I think they are beyond the scope of this discussion (my point was just to say that there are those who say it is fine, so one should not be alarmed seeing a seemingly frum Jew doing so).