The moment people hear this word austerity they get a little frightened. They inevitably associate austerity with going into the forest, eating whatever fruits and roots are available there and exposing themselves to all kinds of risks and sufferings. It is not the body that must undergo the suffering, but the mind. The mind tends towards either sloth and chaos or endless activity, and is filled with the sense of doership and possessiveness. Austerity is putting such a mind with all these negative tendencies that cling to it, through real torture, until all these tendencies let go their hold.
Austerity also means removing the defects that are inherent in the sense organs.
This is the real austerity. There are three types of austerity. One is the physical austerity of the body, the second one is the vocal austerity of the tongue and the third is mental austerity of the mind.