I drink tons of water due to my lung disease. But unless I have lots of fiber, I’m constipated. Started as a child. Was so bad, even my grandmother told my daughter about it! I have steel cut oats few times a week...an apple every day. Mill grained whole wheat bread, from special baker at farmers market. Most importantly, stay away from all white foods… White flour, white rice, white pasta. Replace with Yukon or red 🥔 potatoes, whole wheat 🍞 breads and 🍝 pastas, and brown rice.

I forgot to add but this is not a product that would cause constipation but glutamine is very helpful for the gut. Please Google or look up glutamine.

Back to pooping...if you're not drinking enough water or non-caffeine liquids, nothing willl resolve the issue. Not even that huge amount of fiber I eat will work unless I drink excessive amounts of water. I've always drank a lot of water, carrying water bottles long before they sold them in stores, but the 64 oz recommended isn't enough. Now days I drink between 106-120 oz at least. If I'm outside sweating, I increase it. I have a water bottle that is 30 oz and I drink one before lunch and one after, then 8 oz three times a day with fiber pills, 2 large mugs of decaf coffee, plus unaffiliated tea at meals, and another bottle that's 20 oz is usually consumed throughout the night. It's a lot, but if I fail to get that 2nd large bottle finished, I don't do as well. Here's a trick I use...every commercial or every ad on my phone, I swig up water...at least 4 gulps. Doctor said it's better to drink a little all day long than to drink it all at once.

Good ol prunes! Thanks for a simple good fix.
I dislike drinking a lot of water so I drink various herbal teas throughout the day.
Non caffeinated.
Unfortunately I love my junk food ... potato chips!

I don't know if this would be helpful to you and I don't have IBS but I have leaky gut and they are related I think? Anyway what helps me a lot is drinking warm water first thing in the morning. I always start the day with water. After that I either have roasted dandelion tea or some sort of instant chicory . Some people like ginger . Years ago when I was a teenager I was constipated and my mother took me to a doctor who looked at me and said, "When you feel the urge to go, no matter how small it is, get yourself to the toilet. That was one of the best pieces of advice I've had because I used to hold it in for a while. If my body lets me know that there's a small possibly that I have to go, I go to the bathroom, I listen. Another thing is not to eat food first thing in the morning, drink the water first and try to wait at least 12 hours between your last meal of the day and your first meal of the day. That helps me. And yes, I agree with Annzie about the fiber and everything. Celery has a lot of fiber. I never forget that.