"By fasting it is possible both to be delivered from future evils and to enjoy the good things to come. We fell into disease through sin; let us receive healing through repentance, which is not fruitful without fasting." --St. Basil the Great
"And Jesus said to them, 'Can the friends of the bridegroom mourn as long as the bridegroom is with them? But the days will come when the bridegroom will be taken away from them, and then they will fast.'" --Matthew 9:15
"And let not your fastings be with the hypocrites, for they fast on the second and the fifth day of the week; but do ye keep your fast on the fourth (Wednesday) and on the preparation (the sixth, i.e, Friday) day." --Didache 8:1-2
Fasting is something that is mentioned, but largely unpracticed by modern American Christians. Indeed, fasting-- self-denial-- seems to run at odds with our entire indulgent, consumer culture. But Jesus clearly says that Christians are to fast. "But the days will come when the bridegroom will be taken away from them, and then they will fast."
He cannot be speaking of any period other than the Church age; that is, between the first and the second advent. Christians are called to fast now. So why do modern Christians not fast, and when they do, infrequently and inconsistently?