I know it’s stupid, but I just can’t give up good food. My stomach will hurt so bad it feels like I have back problems or something and I’m still not eating spaghetti without my garlic bread.
I don’t eat the good stuff constantly, most of my meals are bland. When I get a chance though I don’t pass on it.
How sensitive are you? I've found I struggle with them a bit if I eat lots suddenly after not eating them for a while, but if I continue, it tends to be fine. My guess is that the reason it is inconsistent for me is related to fluctuations in gut bacteria partially due to what I am eating...
I know actual IBS is no joke, but I think it would be interesting to determine your threshold and see if you can change it at all. For example, eat a pea-sized piece of onion and wait a couple days. No effect, start eating a pea-sized piece of onion every day and wait for cumulative effects (a week or two?). Still no effect, add another piece for one day, go back to regular dose for a couple days, etc. When you reach the point where it starts to cause discomfort, back off a bit and try to push it again in a week or two.
I've never really tried to change it, I adapted as best as I could.
I'm intolerant to most fodmap (lactose, mannitol, fructans, gos and fructose). I also noticed that gluten can wreck me if I eat too much of it, fatty food can trigger me as well as alcohol.
It was hard to get used to it but now it's a question of self regulation. I skip most of the things that trigger me and indulge sometimes, often a bit too much and I have to face the consequences for up to a week or so. Lactose is the easiest to deal with because of lactase, the rest not so much...
I guess at least I'm not celiac or suffering of Crohn's, so that's that I guess.