What is the best food supplement for someone who has undergone a gallbladder surgical operation?

You had serious surgery and you are asking for medical advice here? Unless you took out your own gallbladder with a sharpened spoon, I would think this is really a question for the medical team providing your post-operative care, or your family doctor, or a professional dietician. You come here for advice about what to do when your boyfriend don't love you no mo' but he wants you to ask your best friend if she'll go out with him. Please, make an appointment to talk to a dietary expert.
Be well
Phil