Juice fasts don’t taste good, won't make you skinny (in any long term sense), and aren't proven to forestall chronic diseases. So why are so many people doing them? The New Republic’s Judith Shulevitz has a fun theory: "People crave the transcendence that comes from self-deprivation." In the absence of religious fasts, juice cleanses and detoxes are a way for people to take control of their shame about their eating habits or their environment and feel purified. Shulevitz writes:
We live in an age of what William James called "medical materialism," so instead of fretting about a fallen world, we speak of a poisoned one. In a modern version of original sin, the corruption of our environment is so thorough that it defies individual efforts to transcend it: "Even those making good lifestyle choices still shower with city water, eat meals at restaurants, and live, work, and shop in buildings that have been cleaned and fumigated with toxic chemicals," writes [Clean Program founder Alejandro] Junger. [...] Distrustful of our surroundings, we try to close ourselves off to malign influences and to purge them.
One important difference between religious fasting and juice cleanses is that Muhammad, Moses, and Jesus didn’t have to pay $425 for the privilege of starving themselves for three weeks.