I’ve been skimming through Adventures in Propaganda (1919), which is made up of the letters sent home to his wife by Captain Heber Blenkenhorn of the American Military Intelligence Division. He arrived in France in summer 1918, so only saw the end of the War, but his book offers some interesting sidelights on things.
There is this piece of propaganda, for example, dropped over the German trenches.
(Click on it to see a larger version)
It is a field postcard, almost the same as the official German one, with these instructions:
” Write the address of your family upon this card and if you are captured by the Americans, give it to the first officer who questions you. He will make it his business to forward it in order that your family may be reassured concerning your situation.”
The reverse side —the message side— had this greeting to the home folks all ready for the prisoner to sign:
” Do not worry about me. The war is over for me. I have good food. The American Army gives its prisoners the same food as its own soldiers: Beef, white bread, potatoes, beans, prunes, coffee, butter, tobacco, etc.”
The effect on ill-nourished troops was, of course, to give them an incentive to come over. (Blenkenhorn claims that droves of them came waving the cards, and demanding an officer and breakfast.) The effect on the worse-nourished civilians who received the cards may have been even greater.
Update: This Daily mail article claims that Germans (or is it mostly inhabitants of occupied countries?) were not allowed sausages during WW1, because the casings material was used to make Zeppelins. http://www.dailymail.co.uk/news/article-2400890/Germans-banned-eating-sausages-World-War-One-intestines-250-000-cows-needed-make-Zeppelin-airship.html