2-4 day fasting brings about a revitalised immune system

Scientists at the University of Southern California have found that 2-4 day fasting causes a drop in white cell counts, and that this effect triggers a stem-cell based regeneration of new immune cells.

Who would have guessed that the ancient ritual of occasional short fasts is beneficial for the health of the body?
It also explains how a simple fast could turn a person's 'diseased' condition around, almost overnight, by giving the body a 'clean out the old, and bring in the new' of the immune system.