Got interested after seeing benefits of intermediate fasting in retreats from noon (more energy more time) - but started to read about benefits of longer fasts now (24 hours - 28 days)
But there is the whole middle way thing to consider - did buddha talk against fasting ? or just against fasting to suffer on purpose thinking that would liberate you ?
If i do it for health benefits it might be ok - right ?
maybe it does have benifits that can help the practice (more energy more time etc).
The object of Buddhist fasting is to eliminate the old habits. (ie:hunger) This should be practiced in a middle way. That is why monks are required to not to eat after midday. If you extend the fasting more than that it becomes the self-mortification. which was rejected by Buddha.
From Nyanaponika Thera's introductory essay to The Four Nutriments of Life, it is clear that the Buddha did not go into the specifics of fasting, as there was no research on the topic at that time. He only taught his disciples to eat between sunrise and noon.
Others, again, have tried to solve the problem of the body's dependence on food by reducing nourishment below sustenance level and by long periods of fasting. This harsh and futile method of self-mortification the Buddha, too, had tried out and rejected before his Enlightenment, and had vividly described his experience in the Discourse on the Noble Quest (Ariya-pariyesana Sutta). Also later on, the Buddha never recommended periods of fasting beyond the abstention from solid food after noon enjoined upon bhikkhus, and in the periodic observance of the Eight or Ten Precepts. What the Buddha, as a teacher of the Middle Way, advised was moderation in eating, non-attachment to the taste of food, and wise reflection on nutriment.
As long as your fasting is not considered to be "self-mortification", then you can do as you please.
