"They will grab food that lies to the right of them ... that lies to the left of them." They will grab food wherever they can find it. (See: [[rc://en/ta/man/jit/figs-merism]])
Possible meanings are 1) people will be so hungry that they will want to eat or will actually eat their own arms or 2) the word "arm" is a metaphor for the person's neighbor. (See: [[rc://en/ta/man/jit/figs-metaphor]])