How is fasting in Christianity different from Islam?

Answer 1

Islam fasting:

In Islam religion, there is the compulsory fasting in Ramadan month (the 9th month) of lunar Islamic (or Hijra) calendar and voluntary fasting in some recommended days for weekly and/or monthly fasting and/or other days. Fasting rules, per Islam religion, is to forbid yourself from drinking, eating, smoking, and doing sex through the period from just before Dawn until sunset. The evening time from sunset to just before dawn, you are allowed to do all what you do in ordinary days (as eating, drinking, and doing sex).

You are exempted from the compulsory fasting in Ramadan due to (for example) health conditions, traveling, pregnancy, or feeding babies. You may required to compensate for these days when the reason for not fasting is no longer valid or you may pay to the poor specific charity for each non fasting day. See related question below for more information.

Christian fasting:

Biblically, fasting is abstaining from food, drink, sleep or sex to focus on a period of spiritual growth. Fasting in Christianity is not required in Scripture, but it's highly recommended. The primary Biblical reason to fast is to develop a closer walk with God. Christians believe that by taking your eyes off the things of this world during fasting, you can focus better on Christ.

There are two references to fasting in the biblical book of Daniel from which the "Daniel Fast" is drawn. Daniel chapter 1 describes how Daniel and his three friends ate only vegetables and drank only water. (Daniel 1). At the end of a ten day trial period, Daniel and his three friends appeared healthier than their peers who ate the rich foods from the royal table. In Daniel chapter 10, Daniel fasts again, abstaining from "choice food," meat, and wine. (Daniel 10).

You may refer to the related link below for more information on Christian fasting and Daniel fasting.