Every major tradition practices it. Ramadan in Islam is a month-long daylight fast. Jewish Yom Kippur is a 25-hour full fast. Christian Lenten fasting has many forms. Hindu and Jain fasts mark sacred days and undertakings. Indigenous vision quests begin with fasting’s stripping.
Fasting works on the body and through the body on the psyche. Appetite, usually automatic, becomes visible. What one normally uses to self-soothe is not available. The mental noise thins, and something else becomes audible.