When I first started my current sort of dirty carnivore/ketogenic diet, I went off of artificial sweeteners, as much to save money as anything else. Adding back in artificial sweeteners doesn't seem to have changed anything, unless maybe I was on the road to being super-ripped.

With the E coli--maybe, but we don't really know effects on other bacteria. One thing mentioned in the study was possible differences when the bugs are exposed to artificial sweeteners with high or low carbohydrate availability.

I did an experiment with inulin as a fermentable fiber once, found I enjoyed it too much mixed with heavy cream. It's slightly sweet, sort of reminds me of powdered coffee mate in the mouth. Now that I live on heavy cream, I might give it another shot. I'm thinking it might give fat bombs a good mouth-feel. I've read it's used in some confections in Japan.