Rejuvenate means to restore to youth, to make young or fresh again, to become young again, to acquire renewed vitality, the renewal of youth, physical, mental and spiritual. The hygienist uses the term, “rejuvenation” to describe the partial restoration of youthfulness to the tissues and organs of the body that may be achieved through hygienic care which includes as a fundamental technique – fasting.

This does not mean turning back the hands of time; it does not refer to turning back the clock. It emphasizes the removal of some of the effects of poor living habits that have accumulated over time and had an adverse effect upon the health and life of the organism. It is very important that we make a distinction between time and things that take place in time. Actions take place between entities. Neither time nor age is an entity. If water constantly drops on a stone, it will wear it away, even the hardest stone, if continued for a long enough period. But it is important to appreciate that it is the water dropping on the stone that wears it away and not the time.

Complete article: http://www.alecburton.com/2009/12/fasting-rejuvenation/