There is a very good book out there for those who believe in fasting, but simply cannot make it past a certain day. Its called The Miracle of Fasting by Paul and Patricia Bragg.
He advocated fasting one day per week, three days per month, and 7-10 days for evrey change of season. The consistency of the fasting, added to a healthy diet, must have worked for him! Paul lived into his 90s. His death is attributed to drowning while body-surfing! (Not a hunched up old man in a nursing home!)