Depends on what you call "quality". I assume you are speaking from a first world point of view, regarding nutrition values, calories, fat, salt and whatnot. Sure, ol'McD [sorry] isn't as healthy as a whole-food salad and salmon plate. But compared to street food found in most 3rd world countries, a Big Mac is usually safer.
It's junk food, and will probably kill you, just not from dysenteria.