This 1942 comic book, available through the University of Nebraska libraries, featured prominent cartoonists telling the American public how they should eat to foster the war effort. Chic Young's Dagwood partakes of one of his famous sandwiches, Alex Raymond 's Flash Gordon "eats plenty of meat," and Lee Falk and Ray Moore's The Phantom advises us that we should have a good breakfast. (Note that Alex Raymond was the cartoonist on Secret Agent X-9, teamed up with Dashiell Hammett).
(Hat tip to the AHA blog. About the image: The well-fed Phantom, by Lee Falk and Ray Moore)