Don't think a diet that requires constant shitting is very healthy.
All that fiber irritates the lining of the colon. Excessive fiber makes problems like IBS, Colitis etc worse.
Harsh fibers like cereal bran etc are not required for human health since humans evolved over million of years without ever eating them. The soluble fiber in fruits and veggies is perfect. How could cereal be needed if they are only around 10k years old?
The only fiber I eat is from broccoli and cauliflower - no cereal, bran, oats etc. Shitting 4 times a normal rate is recipe for colon and anal disorders later on. You wouldn't train a muscle four times a day even though it "adapts" to training. Same thing with your bowels. Wear and tear and overuse applies to all organs of the body, not just skeletal muscle.