Here "Ephraim" represents all the people of Israel. Also "wind" represents something that is useless or temporary. The people of Israel doing things that will not help them is spoken of as if they eat the wind. (See: [[rc://en/ta/man/jit/figs-synecdoche]] and [[rc://en/ta/man/jit/figs-metaphor]])
East winds were very hot and destructive to the land. Here it represents anything that is destructive. The people doing things that will destroy themselves is spoken of as if they are following the east wind. (See: [[rc://en/ta/man/jit/figs-metonymy]] and [[rc://en/ta/man/jit/figs-metaphor]])