What, exactly, is supposed to be this "virtue" in fasting anyway? I fast for 6 to 7 hours every night; I call it being asleep. Like my hero Mark Twain and smoking, I consider the biological necessity of sleep abstinence enough for my purposes.
Otherwise, I "fasted" for 13.7 billion years before I rocked up here and will do for an unspecified amount of time afterward. While I am here I am here to do, not not do. I suppose there's some creepy love of suffering and doing without and mortification of that traditional Christian enemy (the flesh) at work here for the weirdos. For myself, as I say, I am here to do; the grave supplies all its own opportunities for abstinence.