about ounce a month I do a no food water only fast for about 38 hours,Say last meal dinner Monday night ,no eating all Tuesday then eat again Wednesday Morning ) I drink a glass of Water with Lemon and a dash of salt ,sometimes I then take a power dump,sometimes not .That i figure is my colon cleaning itself out. After you make it to about 2:00 pm you don,t even feel hungry anymore and the headaches go away(caffeine withdrawals i think) I always feel better after a fast. It give you digestive system a break a time time clean out old junk.