My gall bladder function was down to 30% and eating even 1/2 gram (0.5 grams) of fat would make me writhe in pain for about 2 hours. Having my gall bladder removed did help, now only if I eat something really really fatty (like non-low-fat ice cream) my side hurts for maybe 30-45 minutes from trying to dump bile since my gall bladder isn't there. No idea what was wrong with my gall bladder to make it lose 70% of its functionality, no stones or anything, but I feel much better now that it isn't there to hurt all the time.
The recovery isn't fun, having little cuts in your abdominal muscles makes you realize that practically everything in moving and breathing uses those muscles, but it sure beats having really bad pain every day that you can't get rid of.