A disciple asked his superior why their teacher did not believe extended fasting was spiritually beneficial.
The superior replied their Guru said mortification of the body not only weakened it, but could also interfere with the kind of intense meditation they practiced.
The disciple responded that he had heard their Guru had actually fasted when he was younger, and asked if that was true.
“Yes”, answered the superior, “but here’s an example of fasting he did. When our Guru went into seclusion to meditate for six days, he would take a bag filled with six loaves of bread to provide him sustenance. At the end of the six days, he would pick up that same bag, and be surprised to find it so heavy. Looking inside he saw the six loaves of bread were still there. This kind of fasting is allowed.”