Austerity is meant to Purify the Mind

In this talk, Swamiji says that the purpose of austerity is to purify the whole being.

In food intake, in the words that one speaks, in the thoughts and emotions that one revolves or encourages in the mind, and ultimately the introspection one does with the intelligence, all these will have to be having a note of austerity, purification! The purification must be for the whole personality.