Fasting is a great idea, but most of the Muslim friends I have eat through out the night after breaking the fast at sunset. I don't think that is very healthy.
Its not particularly healthy, though many ancient cultures prior to Islam have used fasting as part of a way to cleansing of the gut. The relevance to the moon is also from Pagan cultures
Also, Moon is relevant in Islam, as a calendar and timekeeping, nothing to be worshipped.
Also, All Monotheistic Religions have had fasting (the 3 big ones that survived so far) but again, the worst enemy of the people is their own selves and not the devil, and thus they modified what was given to them.