During World War I, the British naval blockade prevented the entrance of food into Germany. To convince British citizens that the blockade was crushing German morale, the British government ran illustrations like this, which claimed that Germans were eating quartz-bread.

This home-front-inspiring chart ran in The Illustrated London News on March 23, 1918. It was designed to portray the Germans as desperate (which they admittedly were) and the Allies as the denizens of a land of plenty. Notice how the wine and beer are labelled with an ominous question mark.

World War I food propaganda claimed Germans subsisted on glue soup

And here's another one from June 18, 1918. This chart suggests that British convicts and tuberculosis-sufferers were better nourished than the German people.

World War I food propaganda claimed Germans subsisted on glue soup

[Via Ptak Science Books]