Cleanses and their cousins, colonics, have about as much medical merit, declared Michael Gershon, a professor of pathology and cell biology at Columbia University’s medical school to The New Republic's Judith Shulevitz, as the acts of penance done by monks who’d “walk across Europe and hit themselves on the back to purge themselves of the plague.”
It's naturalistic theology for people who are more modern than the ones who engaged in crystals and spiritual healing and "The Road To Wellville" stuff - those people who check off "spiritual but not religious" on surveys today - and cleanses are their religious penance.
But for your body, it is truly a scourge. Sure, you will lose weight - it's a diet, 100% of diets cause you to lose weight if you follow them - but in the world where the anti-science left has determined all man-made chemicals are bad and all natural things are good, where cell phones cause cancer, fracking is causing the earth to deflate (and cancer), all radiation is harmful (and causes cancer) but spending $8 for a half cup of kale salad at Organic Avenue will save you, reason has been chucked out the window.
Sorry, progressives, the cleanse just does not work - to really scrub out modern toxins you need a lipid solvent. Like gasoline. And gasoline is not organic so it will never catch on.
The Idiotic Cleanse Craze And The Modern Theology Of Juice Fasts - by Judith Shulevitz, The New Republic