How long did it take you to significantly improve your GI system,
I think it took about a year or so to feel a real difference in my IBS but I still have mild IBS. I explain more about this below. It took probably a year and a half to move myself to fairly mild ME/CFS from moderate.
what treatments/diets made the biggest difference for you?
A low carb diet, 2 courses of Rifaximin and herbal antibacterial herbs were all crucial to my ME/CFS improvements. I'm still doing the low carb diet and herbs. Because I still have mild IBS and haven't fully recovered from ME/CFS yet.
A huge wake-up call for me was when I went off my low carb diet of about 40-50 grams of carbs a day and started eating about 150-200 grams a day of carbs. In 2 weeks I went from rarely ever spending time in bed, to feeling so weak and exhausted, I was spending most of my days in bed!!
Carbs feed inflammatory bacteria in the gut and I believe that's just what happened. Which increased my inflammation, my immune system response and caused me to feel sick, weak and exhausted.
In my case, I'm becoming more and more convinced that chronic stress is what's keeping my gut messed up and maintaining my ME/CFS. It's well established that chronic stress causes dysbiosis and increased intestinal permeability (aka, leaky gut).