There are several things to consider. One is that during most surgeries if not all one will go through a round of antibiotics and this destroys the beneficial bacteria in the gut. This leaves the system vunerable to candida and with the MCs syrup it probably is not a good idea until one has addresed the rebuilding of the bacteria by a period of taking probiotics.
There is also the issue that the body is healing and needs nutrition for the tissue rebuilding faze.
Taking the above into I account personally I would go through a period of very healthy eating while taking probiotics before undertaking any form of fasting. I would do this for 2 to 3 months and maybe longer for more serious surgery.