Fasting has been a Lenten custom from the very beginning of Lent. In our text the Lord Jesus approves of fasting for spiritual purposes - but only for spiritual purposes.
The proper goal of a Christian's fast is to learn self-control. We learn that we can control our bodily appetites and selfish desires. Practicing self-control is a positive, enriching, empowering experience that gives us the dignity and confidence God wants for us as we live His children.