Benefit Diet and Excerise Pre-Op?

I have been doing walking 2-3 miles 3-4 days a week, hula hooping , taking vitamins, minerals (incl. biotin & B12), probiotics and adding protein shakes and soft foods that I will need post op.   I also have some supplement drinks with essential oils and minerals for immediately after surgery to insure that I have adequate nutrition.I'm sure this will help post-op but can somebody give me some specifics on how they think this may help with recovery and success post-op and any additional tips would appreciated.