There is the option of McDonalds -but the thought of eating chain food while spending thousands of dollars on a vacation in Europe (or the US for that matter)is just something that's not appetizing to me. It would have to be the last place open....
But that's me, and if you go to Rome and find a nice romantic restaurant in the Piazza della Rotunda overlooking the Pantheon, a 2,000 year old architectural masterpiece, you look to your left or right and will see many people eating at McD's ...so you won't be alone!