Was diagnosed with IBS just after university, then (similarly) spent 10 years suffering and experimenting when I ended up switching to an ultra-low carb diet for unrelated reasons. Within weeks, I started to feel better and for the next 12 years felt great - so much so, that my family (wanting me to enjoy something sweet) started buying me "Keto-friendly" bars with < 2g of net carbs, but also with erythritol. That was a mistake, as within weeks of enjoying the bars, I was back to dealing with IBS. I'm six weeks into trying to undo the 'damage', and starting to feel a bit better, but I'd definitely advise people who have IBS to always be cautious with trigger foods - certainly the ones that personally cause them issues, but also others on the list.