Doh!
Having several times recommended the excellent book; 'The Death of Grass' by John Christopher on this site. I just remembered there's a film of it; 'No Blade Of Grass'. Which I've also recommended here!
Actually the film is very flawed but the premise; a world wide famine is so good that it is still chilling. What would you do if the only way your family could survive was to kill and rob others? Unlike other post apocalypse films the protagonists aren't saintly strugglers forced to fight by killers. They are the killers.
As often happens there is an american in the group, in the film (so it will sell in america) and they also leave out the reason the famine hits europe overnight. The food ships en route to feed europe from the USA are turned back and no more are going to be sent; because the virus that kills all the grass family (wheat, rice, barley....) is discovered in the americas.
That wouldnt' go down well with an american audience either. But what would you do if you were in congress?

qjs