voluntary fast

"I herewith solemnly declare that if I have to go in to dinner with him again, I will impose a voluntary fast on myself, and not appear at table."

The second voluntary fast was destined to reach the ends of the earth through the public prints.

The third day of his voluntary fast he got a letter.

A snake at the Zoo has even been known to live eighteen months in a voluntary fast, refusing all the most tempting offers of birds and rabbits, merely out of pique at her forcible confinement in a strange cage.