"St. Anthony of Egypt," (252 - 356 AD)
by Hieronymous Bosch
According to the Catholic Encyclopedia, "the word asceticism comes from the Greek askesis which means practice, bodily exercise, and more especially, athletic training. The early Christians adopted it to signify the practice of the spiritual things, or spiritual exercises performed for the purpose of acquiring the habits of virtue."
These spiritual exercises, usually termed "abstinence and fasting," are not by themselves a measure of virtue. According to St. Jerome:
Be on your guard when you begin to mortify your body by abstinence and fasting, lest you imagine yourself to be perfect and a saint; for perfection does not consist in this virtue. It is only a help; a disposition; a means though a fitting one, for the attainment of true perfection.
So, go ahead and undertake spiritual exercise, so long as you understand askesis is a means for attaining sanctity, but is not sanctity itself.