What is the origin of the proverbial phrase, "Drink the Northwestern winds"?
喝西北风，originally as 吸风, from 《庄子·逍遥游》:


  藐姑射之山，有神人居焉……不食五谷，吸风饮露。


Its original meaning is to live with just breathing the air, not eating or drinking anything else. It's a state in Tao.

Nowadays, in oral Chinese, 喝西北风 usually means having nothing to eat because of poverty. For example:


  他工作要是丢了，全家都得去喝西北风。