Here's some good advice:
Fasting is not just denying yourself food. It is exchanging the needs of the physical body for those of the spiritual. Long times of prayer and reading God's Word will be very essential if you are to enter into a more intimate communion with God to maintain your fast to its completion. While fasting, if you dissipate your energy on numerous errands or busy-work to the neglect of spending special time with God, you will starve both physically and spiritually. You will find yourself becoming discouraged and frustrated with your fast instead of being benefited and uplifted and blessed. I don't want that to happen to you.
The more time you spend with God in fellowship, worship, and adoration of Him, and the more you read and meditate upon His Word, the greater your effectiveness will be in prayer and the more meaningful your fast will be. So I encourage you to arrange your schedule accordingly!
