Constipation help....

Okay, my thoughts.

What you describe, getting C from changing to a healthy diet? Unless your diet's fiber content dropped like stone (which would be unusual in the diet you described, but not impossible), or you are not getting enough fluids, that's not normal. I think that's important to think about, you know?

This is not a normal, healthy bodily response to changing the diet the way you've described.

Which likely means something is going on that you may want to know about. Combine that with a previous IBS diagnosis, and that makes it even more likely something weird is going on, honestly.

Obviously nobody is going to know what's going on, but I have a family that had a lot of gut and bowel issues, and so joined a lot of support issues for folks with gut and bowel issues, so I'll just pass on some of the things i've learned, in case they are helpful.

1. Bananas being binding is actually just a myth. It seems to have started because bananas were part of the BRAT diet (bananas, rice, apples, toast) that was supposed to help if you had diarrhea. The premise was literally just speculation by doctors, because these foods 'seemed' like they would be bland and help the gut rest, so they would likely help kids who had a stomach bug and needed to recover. The idea that these foods firm your stools is the result of being in that diet, but it's not true. The BRAT diet has even been abandoned because it isn't all that helpful, in reality. (although to be fair, very, very under ripe bananas can cause trouble, but they are typically unpleasant to eat too).

2. Have you ever been checked for celiac disease? Celiac disease is often misdiagnosed as IBS in early stages. Celiac disease can cause diarrhea OR constipation, depending on the person. Docs don't know why, but it happens. I know that sometimes you'll see a reaction to increasing wheat products when someone is trying to eat healthy (like having more whole grain pasta, say), and that can be a clue that something is going on.

Celiacs just have to eat gluten free and the problem goes away. But first, the level of gluten free is very intense, down to peanut allergic folks avoiding peanut contamination, so it's a pain to do if you aren't a celiac. And second, you can't be tested for the disease once you stop eating gluten and start healing up, so it's best to get tested before changing diet.

3. some food intolerances or reactions involve C. so if there are foods that you are eating more of, it could be as simple as one of them not being tolerated by your body and you are reacting more now that you are eating more.