The hypothesis is that most people benefit from an unirritated colon full of enough volume, from fibre and liquid, to stimulate movement.
1) dial back common irritants such as gluten, dairy and the worst FODMAPS such as garlic and onions, alcohol.
2) encourage liquid in the colon by dialing up foods that contain liquid, drinking, putting miralax in your coffee until you are healthy enough to taper.
3) move flexibly toward a unprocessed foods vegan diet as easy way to dial up fibre. The idea is to be eating A LOT of natural foods that are not calorie dense. Start measuring your daily fibre intake. Keep upping it until you achieve results. Try to get to 50 grams.
4) drink light roast coffee in morning which has more caffeine, and more is better. Bulletproof it with butter rather than cream or milk to dodge milk proteins and lactose.
5) once you start getting results, start drilling in on how to get protein ie eggs, chickpeas, quinoa, nut/seed butters and carefully with small portions of lean chicken and fish to see if you can not backslide on fibre and results