The posters of World War 1 are often wordy and dire, compared to those of the Second World War that were more like modern advertising As Corey Bernat noted in the Smithsonian,
Most of them are not really about food—they're about behavior modification. Both times, with both wars, the government needed the public to modify their behavior for the national good. (And today, that’s exactly what Michelle Obama is trying to get people to do: change their behavior to curb childhood obesity.) As the Food Administration's publications director put it to state officials back in 1917: “All you gentlemen have to do is induce the American people to change their ways of living!” He’s saying it with irony, of course, because that's a very hard task.