For some fascinting biblical examples of the purpose of fasting:


The Disciple's Fast:

"To loose the bands of wickedness" from ourselves and others. Isa 58:6, Matt 17:21


The Ezra Fast:

"Undo the heavy burdens."  Isa 58:6, Ezra 8:23


The Samuel Fast:

"To let the oppressed (physically and spiritually) go free." Isa 58:6, 1Sam 7:6


The Elijah Fast:

"To break every yoke" conquering mental and emotional problems. Isa 58:6, 1Kings 19:4, 8


The Widow's Fast:

"To share our bread with the hungry" and to care for the poor. Isa 58:7, 1Kings 17:16


The Paul Fast:

To allow God's "light to break forth like the morning," bringing clearer perspective and insight as we make crucial decisions.

Isa 58:8 Acts 9:9


The Daniel Fast:

So "thine health shall spring forth." Isa 58:8, Dan 1:8


The Esther Fast:

That "the glory of the Lord" will protect us from the evil one. Isa 58;8, Esther 4:16, 5:2