Besides total fasting, one can observe a partial fast by giving up only meat or salt for a day. A moderate fast may mean subsisting on liquids or one meal a day. Fasting is a concept that exists in almost all religions, in every culture. These days, it is also being used as a form of protest or a non-violent way to make a statement. Mahatma Gandhi popularized the idea of fasting as a means of protest when he launched a campaign of liberating India from British rule through non-violent means in the 20th century.
Many people believe fasting promotes self-control and strengthens the body as well as the soul.
Growing up in India, women around me were usually observing fasts of some kind or the other, either to propitiate a particular deity, or because it was a religious occasion. I used to marvel at how my mother would prepare a feast for us during a festival and not even take a little bite until the sun set and she had finished her evening prayers. Even then she would break fast by eating fruits or something light instead of splurging on the heavy dinner she had prepared for us. Having grown up in such an environment it is all the more embarrassing for me to admit that fasting is beyond me. I can't even diet decently, let alone abstain from food all day.