Digestive changes after gallbladder surgery are a little like pregnancy in that no two people react the same. Generally you will not process fats as well. Too many fats at one sitting will cause problems. Some people can never enjoy fried chicken again while others can tolerate it only in moderation. Eat a low fat diet for several weeks after surgery then add back fats until you establish your particular tolerance. Watch out for odd foods or spices that give you indigestion. I know several people that have problems with garlic. My only long term problem is with too many fats at one sitting. A sandwich with French fries is so yummy but it is not worth the after effects. I will burb up gobs of pure fat that obviously I don't have a gallbladder to process any more.
The good diet after removing the gallbladder is what a normal person takes. In which he should eat fish, fresh vegetables and fruits. Take a normal diet because special dieting is not required after the gall bladder is removed. It is only required when you have other unrelated problems like diabetes.