After John had baptized Jesus, we read in Luke 4:1-13 that Jesus was led by the Holy Spirit into the desert where, for forty days and forty nights, the devil tempted him.
Although the scriptures is silent on Jesus' daily activities during the forty days and forty nights fasting, we read in Mark 1:13 that "He was with the wild animals, and the angels attended to him."
To put it into context, the desert is a desolate place covered with sand as far as the eyes can see, with very little human activities, particularly in 27 AD when Jesus did his forty days and forty nights fasting. Only in the oasis would you find water and lush vegetation, and as a rule people seldom ventured too far from the oasis.
The desert can be extremely hot during the day, cold at night, and sand storms are common events. Protection from these elements came from taking shelter in caves on the slope of hills, and covering one's face with linen to protect the eyes from air bound grains of sand.
There are no furniture in desert caves, and those who lived in them slept on animal skin spread on the bare ground, and used stones as pillows. To a modern person, such accommodation is nothing short of torture; yet Jesus spent forty days and forty nights under these conditions, so that the word of God could be brought to all humankind.
Anyone who has fasted for three days and nights would have experienced only minimally the immense physical hardship Jesus endured during his forty days and forty nights fasting in the desert.
For its comfort, the body exerts tremendous pull on our attention and resources to meet its needs. It is no surprise why huge number of offices, stores and factories all around the world are geared solely toward producing goods and services to satisfy the demands of the human body.
Consequently, it requires extraordinary effort, some may say divine help to subordinate the demands of the body to the demands of the soul by fasting. To say it another way, fasting subordinates the demands of the physical person to the demands of the spiritual person.
To succeed in a fast, the pull of the body's demands on our attention and resources should be temporarily suspended: temporarily because no one could fast indefinitely without ending his or her life.
The struggle between the physical person and the spiritual person for dominance over our attention and resources produces the hunger pangs we experience during fasting. When we don't succumb to the hunger pangs, we give the spiritual person control over what our minds and bodies do and say.