follow your doctor's requirements. The surgery isn't only focused on you. You have hired a team to perform the procedure and it's neither fair or prudent to do anything that would compromise their work. Think of yourself as the canvas and the medical/surgical team as the artists. Should they do their best work using the best techniques, paints and brushes on an ill prepared canvas. Would you expect them to do a mediocre job. How would you feel as a provider finding out that a patient hasn't kept their part of the preparation and it affected your ability to perform the very best procedure.