Some denominations do not practice it, considering it an external observance, but many individual believers choose to observe fasts at various times at their own behest.

In hijrah event when Muhammad led his followers to Medina, he found the Jews of that area likewise observing fasts on the day of Ashura.

Rabbi Zadok observed fasts for 40 years in order that Jerusalem might not be destroyed.

Christians, Jews, Muslims, Confucians, Hindus and adherents of other religious faiths observe fasts.

Additionally, throughout a given year, Orthodox Christians observe numerous fasts (such as Lent), during which food is prepared without any meat or dairy products.

Many devout Muslims observe fasts during the month of Ramadan, which ends in celebration at Eid ul-Fitr.

Thathai Bhatias are a religious community, and observe fasts on auspicious days to please the gods.

He would observe frequent fasts and would scourge himself daily.

It is common among orthodox Iyengars to observe fasts during certain months of the Tamil calendar, as also yearly pujas during the month of Margazhi.

Babylonians were known to observe fasts as penance for sins committed in the eyes of God.