For example, if your colostomy was created because of a low rectal tumor and the resection removed the rectum and the anus, your colostomy is permanent. On the other hand, most colostomies for perforated diverticular disease are reversible. There are circumstances when colostomy reversals are just technically difficult and reversal is aborted. Or if the risk of the surgery outweighs the benefit of reversing it then it is permanent like an elderly person with a bad heart.
That being said, a handful of patients experience loose stools for a few weeks after their gallbladder is removed. In those instances, I recommend that patients do adhere to a low fat diet till the loose stools resolve. This usually is self limited and resolved within a few weeks.