Why do Muslims fast and isn’t it harmful to them?

Fasting is regarded as a physical, moral and spiritual discipline for the purpose of promoting righteousness.

The fast places everybody, rich and poor alike, on the same level.

The wealthy experience the same pangs of hunger in the same manner as their poor brothers. The result is that they become more sympathetic to the poor and poverty-stricken.

Fasting is believed to increase will power and curb bodily desires and habitual self-indulgences. Fasting is also acknowledged by most medical experts as an excellent means to curing obesity, and expelling harmful toxins from the human body. Furthermore there are exemptions for sick people, pregnant mothers, wayfarers, and other reasons. If they can afford they can send monies to poor people as expiation.