We may need to adapt and change our eating habits if corn, or some other staple of the American diet were to become scarce or too expensive. Adapting is not something we Mercans particularly like to do, but we can, if we need too.
If there were some kind of catastrophic event where there were rumors of shortages, I worry that Americans, with the help of the entertainment-news channels like FOX and CNN, will create a food shortage and runaway pricing by hoarding.
And while some will use their guns to hunt game, I worry that gun owners in urban and suburban areas would arm themselves to "protect" their family's hoard.
And, it goes without saying, if we do have a food "crisis" here, big corporations and wealthy commodity traders will get richer off of it.

Anyway, like FDR said, "We have nothing to fear but fear itself." We stand to be hurt more by rumors of shortages than by shortages themselves.
CD