Fasting means willings giving up on food or restricting some food groups for a period of time. A dry fast is a fast where you abstain from all foods and liquid for 24 hours. Water fast is fast where you are only allowed to drink water. Fasting is not something restricted to Muslims, people all over the world fast in one way or the other. Buddhists, Christians, Hindus, Jews all fast. Of course, the way fast is observed in each religion differs. But one thing is certain, people have been fasting since centuries. Surely, they must have realized benefits of fasting.