Earlier quoted context omitted.
I can really see that, $5 gets you a LOT at Taco Bell (funnily enough, they refused to load any images till I switched my IP to a USA one O.o). I’m actually shocked how much you get. Here in Germany, McDonalds / Burger King (not sure what other fast food places we have) are disgusting AND expensive :D
Cheap (and even not so cheap) "Mexican" food in particular is a great opportunity for the restaurant to bulk up a little protein with lots of cheap filler like rice and beans. With a burger, you have a floor set by a certain weight of ground beef. And, yes, while I very rarely go into a McDonald's or Burger King, my sense is that they're not a particularly cheap meal. And the better "fast casual" burger chains certai…
Rice and beans make a complete protein. You're writing as if people are getting less protein than they expected, but the inclusion of beans means they're probably not.