The Bahá'í Fast begins

One who performeth neither good deeds nor acts of worship is like unto a tree which beareth no fruit, and an action which leaveth no trace. Whosoever experienceth the holy ecstasy of worship will refuse to barter such an act or any praise of God for all that existeth in the world. Fasting and obligatory prayer are as two wings to man's life. Blessed be the one who soareth with their aid in the heaven of the love of God, the Lord of all worlds.

Bahá'u'lláh, The Importance of Obligatory Prayer and Fasting, (compilation)

The Bahá'í Fast takes place from 2nd to 20th March and is a period of cleansing and renewal. During this time Bahá'ís do not eat or drink between sunrise and sunset. Turning away from food and drink reminds man that he is a spiritual as well as a physical being.

It is not enough to just abstain from food and drink though, it is the spirit in which one approaces the Fast that is important. One should spend time in prayer and meditation and consider how to improve our lives. This spiritual preparation helps us begin the new year, which starts immediately after the Fast, strengthened and invigorated.

Well is it with you, as you have followed the Law of God and arisen to observe the Fast during these blessed days, for this physical fast is a symbol of the spiritual fast. This Fast leadeth to the cleansing of the soul from all selfish desires, the acquisition of spiritual attributes, attraction to the breezes of the All-Merciful, and enkindlement with the fire of divine love.

'Abdu'l Bahá, The Importance of Obligatory Prayer and Fasting (compilation)