The shift to a carnivore diet, eliminating fiber, can initially cause diarrhea due to unresorbed bile acids.

“i believe there are bile acids that are not resorbed in the small intestine and if you get rid of all the fiber which has been uh removing those bile acids from your colon so they don't end up in your colon it's been preventing them from showing up in your colon as naked bile acids which will cause catharsis they will pull water into your colon you'll get watery diarrhea”