What’s better to drink on a 0‑calorie diet?

[quqal]

What is better to drink during a fast: green tea or water?
As far as I know, green tea acts as a diuretic, which helps reduce swelling and cleanse the kidneys, right?
If I’m wrong, I’m sorry. If it’s not too much trouble, could you explain it? I don’t really understand all of this.

 

[_Leech]

I would just drink water