fasting is a great act of worship for the muslim which he performs by neglecting his desires to please his lord and hopes for his reward. it just common sense that the one who would not give up desired things except that it would be for something more desirable. in this case the pleasure of allah is the most sought after desire.

it is also a means of achieving piety and righteousness. the prophet (peace be upon him) said: "he who does not give up false speech and evil actions, allah doesn't need his refraining from food and drink."

in other words, allah is not going to accept this person's fasting.

the heart, through fasting, is apt to maintain its tenderness since the desires are not sought rather shunned, and tend to be more receptive to the words of allah.

the rich will, through fasting be more appreciative of allah's graces and bounties. he will also suffer deprivation as do the poor and needy under their everyday circumstances. so he will be more motivated to help them from what allah has provided him. it helps depress pride of the ego and maintains humbleness. moreover, fasting has its health advantages by virtue of decreasing the intake of food and relaxing the digestive system. great is the wisdom of allah, and great are his graces