Here "bread" is a metaphor that points to Jesus who is the one who gives spiritual life just as bread sustains physical life. AT: "I am like the true bread" (See: [[rc://en/ta/man/translate/figs-metaphor]])
Here "the world" is a metonym that represents the lives of all the people in the world. AT: "that will give life to all the people in the world" (See: [[rc://en/ta/man/translate/figs-metonymy]])