There is a fasting that gives up something.  There is a fasting that adds something.  There is a fasting that is self-denial.  There is a fasting that is to restore the denied.  There is a fasting that gives up food, and there is a fasting that feeds the poor, frees the oppressed, clothes the naked and gives hospitality.  So, as you think about fasting, think of both negative and positive fasting.

“Is not this the fast that I choose: to loose the bonds of wickedness, to undo the straps of the yoke, to let the oppressed go free, and to break every yoke?  Is it not to share your bread with the hungry and bring the homeless poor into your house; when you see the naked, to cover him, and not to hide yourself from your own flesh?  Then shall your light break forth like the dawn, and your healing shall spring up speedily; your righteousness shall go before you; the glory of the LORD shall be your rear guard. Then you shall call, and the LORD will answer; you shall cry, and he will say, ‘Here I am.’” Isaiah 58:6-9a (ESV)