Well.... prebiotics, and probiotics. I drink kefir (liquid yogurt drink). I’m Russian, so I love pickled foods. Like you, saurkraut and very few carbohydrates, other than fruit and veggies. Cooked beets. We Russians love our beets. Lots of water. I added a fiber drink in the afternoon and a fast acting laxative if I get backed up (lost a couple feet of colon , so not as much storage area) It works and then it doesn’t, so then I change it up. I’m lucky that I have been able to control with mostly food choices and supplements. I know that. But, always watching out for changes in how my body works.