July 21 is (unofficially) National Junk Food Day in the U.S. Whether we like Burger King, McDonald’s, Taco Bell or something else entirely, we all know the pleasure of an occasional indulgence in the greasiest food we can get our grubby fingers on. There’s something about the fast food experience: forking over a couple measly bucks for instant gratification in the form of potatoes and dirt-cheap cuts of meat cooked in the fattiest oil allowed by law.