While kava didn’t slow down my caffeine intake, I’m definitely in the camp with people who inadvertently stopped drinking after using kava regularly. I was several months down the road before I even noticed.
I was never a heavy drinker-tapping out after just two of any drink, but I worked a place where drinks after work was a daily thing, (provided by the company, even) so to accidentally stop participating in this culture without noticing is kinda huge. I imagine if you’re drinking lots of caffeine it could have a similar effect.
I will still accept a drink on the right social occasion but my taste for alcohol has diminished significantly and my tolerance even more, since switching to kava.