I tried it 2 years ago before my diagnosis. I was feeling awful and the many specialized drs I went to could give me answers. It did help, it was very hard to do with a busy family lifestyle, and it took about 2 months before I really started to notice I was feeling better. But I fell off the AIP wagon.
Fast forward 2 years, feeling even worse than ever but I found a great rheumatologist and I now have my AS diagnosis. I decided I needed to hit this from every angle I can so now I'm doing humira and a very restricted paleo/AIP type diet. I'm struggling trying to make/have good foods on hand. My herbalist says eyrthritol is ok if you can tolerate it. I have had years of GI problems and my stomach doesn't tolerate much. I am noticing a difference, I am able to do more, my body isn't as inflamed as it was. I used to wake up so swollen every morning. I just feel enough better overall that it is worth it. I'd say give it a try and see if it works for you. I've really wanted a glass of wine or a cocktail but I haven't felt good enough to try it yet.