In response to the enquiry: “Does fasting hurt the kidneys?”
It depends on how one fasts, how long one fasts, and how often does one fast.
Ramadan fasting lasts only during the day. A big meal awaits in the evening.
One gets hungry usually about 12 to 18 hours after one begins fasting.
Absolute fasting by not eating and not drinking for a day does not seem to harm the kidneys provided that urination is normal.
Not eating solid food but drinking hot water or hot tea while staying away from all sugared drinks will help flush the kidneys.
What hurts the kidneys are a lot of red meat, a lot of pork, too much acidic drinks and sugared drinks, too much orange juice, etc.
Unsweetened cranberry juice seems to help “cleanse” the kidneys.
Diuretic herbal teas also seem to help a little in “cleansing” the kidneys.
A vegetarian diet of absolutely no meat seems to “preserve” the kidney.
A diet of vegetables and fish does not seem to bring on kidney pain. A diet of a lot of pork and red meat seems to bring on kidney pain.