Smoking is a falsification of the natural instinct of the body to preserve its own inner cleanliness as well as an insult to its sensibility to irritating odours. If smoking is actually enjoyed as a pleasure, that merely shows how false have become the habits imposed on the body's natural instinct. He who desires to rid himself of the smoking habit must therefore restore the operation of this instinct. Among the various techniques that he will have to adopt, one is that of fasting. Short but regular fasts will help to purify him and give back what he has lost--the true instinct of the body and the senses. When this instinct is restored, the desire for smoking will begin to fall away of itself, and indeed an aversion to it will replace it.
-- Notebooks Category 5: The Body > Chapter 3: Diet > # 42