When Jesus fasted for forty days and forty nights what did he fast for?

In Biblical times people often fasted in search of a more perfect faith. It is thought to be easier to listen to or connect with God when one is not distracted by worldly activities. (From a strictly scientific standpoint, people may have inadvertently discovered that not eating for an extended period of time causes hallucinations and interpreted those hallucinations as messages from God - or maybe they really were, who knows?)

The Book of Matthew specifies that Jesus went into the wilderness to be tempted by the Devil. Fasting may have been an incidental side effect.