3 Types of Fasting

From Spiritual Journey of the Mystics:

There are three types of fasting:

1. The fasting of commons, which is the renunciation of eating and drinking, and observance of other fasting requirements as described in the Books of Jurisprudence.
2. The fasting of nobles, which in addition to the above also includes renunciation of sins i.e. controlling eyes, ears, tongue, and other bodily parts from sinning and transgression.
3. The fasting of most distinguished nobles which in addition to the renunciation of the above also includes relinquishment of everything, be it permissible or forbidden, which makes mind and conscience negligent from Allah's remembrance.

Of course, it must be understood that even the fasting of noble and the fasting of most distinguished notables in itself contains infinite degrees and ranks, i.e. like the believers containing various degrees and ranks in accordance with their piety and asceticism, inevitably their fasting too will differ on the basis of the magnitude of their piety and asceticism. Considering that each believer possesses a particular degree of faith and piety, it could be said that faith, piety, and fasting have as much as ranks and degrees as there are the number of believers.