Years ago, I once took a bet that for a week I couldn't have any alcohol, sex, food or masturbate heh. I won
However for actual health, it can be beneficial but not for weight loss. Once a year for a week is a good thing, even if your body can clean itself, you can always help it do its job you know.
However, don't stick with only tea or lemonade or something. Do this:
Eat as much fruits/vegetables as you wish, no limits, and obviously as much water as you want. You can blend the fruits/veggies into a shake if you wish, just don't use any of the sugary fruit drinks from the box.
Here, you don't need to miss any nutrients/vitamins and just eat as much as you like when you feel hungry, you'll do fine.