Women were used in WWI U.S. propaganda posters to show the public larger than life ideas. Sometimes the women’s beauty exemplified the beauty of the idea they were promoting, like in the “Liberty sowing the Seeds of Victory” poster (top). Sometimes sex-appeal was necessary to get the point home, like in the Third Liberty Loan poster (bottom). Sometimes, however, it was simply for the sake of anthropomorphizing a concept, like in the “Sugar means Ships” poster (middle).
You can see Lady Liberty here twice (top and bottom). She is metaphorically sowing seeds through the new home farms and encouraging the audience to buy war bonds. Notice the difference in sexuality between the two. The one urging people to buy bonds is rather risque for her time, making the poster stand out quite a bit. The top poster plays on the audience’s sense of duty, she’s more reserved and distant like a moving mountain.
The US government told American men, women, and children to ration their food. Organizations like the Food Administration used posters to urge citizens to reduce their personal consumption of meat, wheat, fats and sugars so they could provide for soldiers fighting. Whether they served in the military, Americans could assist with the war effort. Even the simple act of consuming less sugar meant more ships to help in the war effort, because most American sugar came by ship. 
Contributors: Summer Crisler, Rachel McGee, Seth Palitang, and Makaylah Collins