you must read the whole discussion if you want to know the answers : or look at any of the links given in it
fasting is not eating solid food, rather just drinking water, or using liquid foods such as fruit juices, milk, broths
from what i have read, the body does not go into starvation until 30 days of no solid food, usually people fast for 1-3 days or a week at most, but it can be quite challenging.
the body is an energy system of electricity
when you fill it with lots of things, then most of the energy is used for digestion
and,
when you have nothing to digest, the energy goes elsewhere, producing clarity and spiritual bliss,
it is a rough process and not for many, however, it is good for cleaning the body of many toxins, some people have passed tumors out of themselves, by going on a fast for a while.
a reason to fast might be, say you are obese, you eat lots of junk foods, so you start going vegan, and once you accept that, and get used to it, then from vegan you switch to fruit juice fasting for a few days, and you just are basically, cleaning your body’s junk out, in a way that you still feel comfortable, while making sure your nutrition is still prime.
my meditation teacher drank only apple juice and some sort of supplement that is basically clay for 15 days and she said it wasn’t hard at all, but i’ve yet to try
if you drink fruit juice (fresh stuff) every time you are hungry, you can have strong bliss and fresh perception, without really getting tired, but maybe this is only half a day, or one day, depending on how your body is and how long it can handle it.
after very long fasts you have to be super careful what food you eat, and only eat the tiniest bit of it, and wait 30 minutes before taking another
like, 1 tiny bite of apple, and waiting 30 minutes
since the body is used to being empty.