We live in a culture that demands that its appetites be satisfied. Whether this is food, alcohol, sex or rest, we see it almost as a human right that we get what we want. Even the Rolling Stones questioned that! To go hungry is something to be avoided and the nearest thing we get to it in this culture is to "detox".
But why fast? Is it simply to show God how pious we are? Isaiah 58:6-8 makes clear what our fast should be like.
"Is this not the fast which I choose, To loosen the bonds of wickedness, To undo the bands of the yoke, And to let the oppressed go free And break every yoke? "Is it not to divide your bread with the hungry And bring the homeless poor into the house; When you see the naked, to cover him; And not to hide yourself from your own flesh? "Then your light will break out like the dawn, And your recovery will speedily spring forth; And your righteousness will go before you; The glory of the LORD will be your rear guard."