There are many times of fasting written about in the bible. They all take place around very important events, or when something of great importance was being prepared for.

Take for instance Queen Esther. She was faced with the somewhat daunting task of risking her own life to present to the king a case for sparing the Jews of the nation whom the king had agreed to destroy. When asked by her uncle Mordecai if she would make a stand, her first response in agreement was “Go, gather all the Jews who are present in Shushan, and fast for me; neither eat nor drink for three days, night or day. My maids and I will fast likewise.” Esther 4:16. Her first point of strategy was to call a fast. She knew that something happens in the spiritual when you fast.

Jesus fasted forty days and forty nights while He was in the desert, before He was tempted by the devil. After His victory against the enemy, He was baptized in the Jordan then began to preach. The fasting preceded great spiritual breakthrough.

In Acts 13, Barnabas and Saul (Paul) were about to be sent off into ministry as it were. But first, they fasted and prayed and were prayed for with the laying on of hands. (Acts 13:3)And then later on, they themselves prayed and fasted for the elders they were appointing within the church.

The point of fasting is to focus on God. It is to take the focus off some of our worldly things and look to Him. It is to combine the fast with prayer. If there is no prayer, then it is really just going hungry!
You do not necessarily need to fast from food. Some people are unable to for medical or health reasons. Some people fast from television, or coffee, or magazines etc. There is no ‘prescribed’ period required for fasting. And certainly, with Thursday’s Babies, it is a suggestion not a demand!
I know for me, quite often there will come a point later in the day where I feel it is time to break the fast. Because I fast every week, I allow myself to drink nice drinks on those days (hot chocolates, juices etc). But a fast is really between you and God. Ask Him what He would have you do, then be obedient to His leading.