I make my own full-fat kefir, and drink it in a smoothie for breakfast with Isopure protein powder (lc) and about 20gr frozen blueberries. If you look at my diary, you can see the carb counts. I log it with a member supplied entry called "Homemade - Whole Milk Kefir" that logs 6 carbs per cup... dunno how accurate it is. YMMV. I think it would depend on how sensitive you are to insulin spiking? I am not diabetic.

Water kefir is a great alternative to pop or tea when wanting to drink something other than diet, coffee, teas or water.

Its relatively easy to make water kefir. And yes, if you do a secondary ferment ~ the right amount of time, it will have a tiny amount of sugar or none left. You can taste the sugar ~ if its still in it. If you can taste it, you let it set on the counter-top another day or two. In 1-4 days, it will have no sugar in it. You can sweeten it with a prebiotic sugar called, "inulin", the brand I use is called, "Just Like Sugar". (Amazon)

If you haven't done it before, YouTube is your friend. Basically, you do the initial ferment with the grains, then a secondary ferment with a sugary fruit juice or pureed fruits/berries (in a separate bottle that has a cap, so it can get fizzy).

I highly recommend it to families that have kids, let the kids be part of making it. It is much healthier than sugary pop and probiotic to boot.

I hope this helps,
Dan the Man from Michigan
Keto / The Recipe Water Fasting / E.A.S.Y. Exercise Program