What metaphors are used in A Moveable Feast by Ernest Hemingway?

The theme of hunger recurs throughout the book, both physically and metaphorically. Hemingway uses physical hunger to sharpen and discipline himself, as he describes in the chapter called "Hunger is Good Discipline." He writes about how he willingly forgoes lunch in order to make himself hungry, telling himself that he cannot afford the extra food and telling his wife that he is going out to lunch with friends.