It is said that Pythagoras routinely fasted for 40 days because he believed that fasting improved physical and mental health. He even required his students to observe fasts. New students were also required to fast before he accepted them into his school.
Greek and Chinese philosophers are known to have fasted and most religions advocate fasting too. Yoga advocates fasting also.
A few months ago I undertook a water only fast for 1 week and my experience is that, besides some physical benefits, I had much better clarity of mind and my emotional disposition became very positive. This effect lasted for about 2 weeks during which time it faded. About 3 - 4 days after I had broken my fast I had a breakthrough insight related to trading.
Has anyone here considered fasting to improve mental clarity? If so, I would love to hear about your experience.