If you are thinking about doing a "Cleanse"

TheWorstHorse

From Thinner This Year by Crowley and Sacheck:

The idea that a detox can purge certain (unnamed) toxins that have invaded your body through a near starvation diet for a few days or even longer, lightened with a magical combination of juice and herbs, defies logic. You do some penance, scourge yourself with magical elements, and drive the evils out of your body. It is an appealing notion, so you can see why it has been around for a long time (the ancient Egyptians were doing it). It is also complete nonsense.

There is no evidence that cleanses do you a bit of good. And -- to those with some understanding of how the body works -- it is hard to imagine how they could.