As in, if it tastes sweet but is not absorbed in the small intestine, so has "no calories", it will inevitably all pass on to the large intestine where it can be fermented.

As someone who absolutely hates the synthetic taste of aspartame etc. but has to stay on a low-FODMAP diet, I've just resigned to eating stuff with ordinary sugar and using sufficient moderation.

We got a Ninja Creami, it's not a traditional ice cream maker, you freeze these pint cups, then run them through the machine and it shaves it then blends it. My preferred recipe is: a quarter cup 0% yogurt, 2-4tbs allulose, pinch of xantham gum, the remainder fruit (strawberry, blueberry, canned low sugar pears or mandarin oranges or pineapple or peaches). This is delicious, low calorie (140-240cal per pint), and low sugar. It hits all the "ice cream" centers in my brain.

My wife takes it much fancier, she will make a vanilla base, and then often make low sugar mix ins (fudge, choc chips, caramel (with allulose), peanut butter cups (with PB2), marshmallows).

The Creami is noisy as hell for 3 minutes, and I wasn't sure how much we'd actually use it, but we've used it a lot. We got it on sale, about half price, which made it easier. Woot sometimes has them about this price (more like $100 than $200). One down side is that you basically have to re-blend it every time you want some, the remains largely freeze back into solid, though if you hit it with the microwave for 20 seconds you can kind of chunk it up and eat the flakes. Not really ice cream at that point.