Nice article at the link above.
What we do know: if you had something inside that was stuck and needed to be cleansed out, you’d likely be demanding some medical attention right away. It’s not a stealth issue.
Also we know eating vegetables and fruits is good.
What we don’t know: everything else about juicing. We don’t have a comparison of the benefits of kale juice vs, eating kale, and we don’t know what happens to kale juice in your fridge vs what happens to kale. I’m using kale as an example since personally I’d rather drink it than eat it.