It’s a lovely drink, and yes, the fermentation has great health benefits, but think of it as healthy “pop”. (sugar, caffeine, alcohol content puts it in that category)
You could add in a kombucha once in a while as a treat post challenge, (or enjoy with your treat meal during the challenge) and it would be a great option instead of alcohol on a night out. (some restaurants have it on tap now)
But for the duration of the challenge, we recommend you stick to water!