The social effects of fasts are not concealed for anyone.
Fasts impart the message of equality amongst the individuals of the society.
By acting upon this religious obligation the affluent ones not only experience the hunger of the hungry and the impoverished ones of the society, first hand, but economizing on their daily food also serves to benefit them.
Yes, it is possible to draw the attention of the affluent ones towards state of the hungry and the deprived ones by describing their conditions to them, but if this aspect were to be experienced personally and physically, the effects would be all the more noticeable.
The fasts provide a personal and physical experience to this important social issue. And it is for this reason that it has been narrated that when Hishaam Ibn Hakam sought to know the reason for the legislation of the fasts, Imam Sadiq (peace be upon him) replied:
The fasts have been made obligatory in order to establish equality between the rich and the poor; and this, in order that the rich experience the pangs of hunger and thus fulfill their obligations with respect to the poor.
Usually, the rich can attain whatever they covet; God desires that there exist equality between His servant and so makes the rich to experience hunger, pain and trouble so that they may exhibit mercy upon the hungry and the destitute.(1)
If the wealthy nations of the world were to fast for just a few days in the year and experience the pangs of hunger, would all these hungry ones still continue to exist in the world?
source : tebyan