Fasting is the voluntary denial of "normal" activities for the purpose of focused and intentional spiritual activity.
FASTING IN SCRIPTURE
Every example of fasting in scripture involves refraining from food for a spiritual purpose.
There are three types of fasts recorded in scripture
- Absolute Fast - no food or drink, including water (ex: Exodus 34:28)
- Normal Fast - only water is consumed (ex: Matthew 4:1-2)
- Partial Fast - some foods are consumed while others are restricted (ex: Daniel 1:8-16; Daniel 10:2-3)
- An act of worship (Romans 12:1)
- Starving your flesh for the purpose of feeding your spirit (1 Thess. 5:23; Matthew 6:25)
- Always a time focused on prayer and God's Word. You can pray without fasting, but you cannot fast without praying
THE HEART OF FASTING
What is common between every type of fasting in scripture is the giving up of things for the purpose of greater fulfillment.
We tend to rarely go without things we need or want and as a result tend to find our fulfillment and have our needs met in/by these "things". These things may not be bad, and can even be good (as with food), but when we find a fulfillment in them that's not as God intended, or that's even in place of God himself, that becomes a problem and a hinderance toward our intimacy with the Almighty. Once we identify things that can take our time, attention, or affection away from God, we can offer these things as a sacrifice, by giving them up, whether permanently or for a time, in order to pursue deeper intimacy with Him.
If you boil it down... HOW you fast is far less important than WHY you are fasting and WHO your fast is about!