The concept of a period of fasting, or self-denial of some kind, a regular one, is in many religions. I've seen the attraction, but never particularly participated, until one was thrust upon me last year -- an involuntary abstinance from wanking.
I'm participating in it again this year, for spiritual and personal growth and great justice. Patience. Patience is a virtue.
Many religions have their period of quiet and so forth in the dead times of the winter -- Wicca's is from Samhein to Yule. I am the backwards one, so I'm declaring my time of quiet from my birthday to the summer solstice. I should probably properly declare it from Beltane to the Summer Solstice, but that's when I have Things to Do.