I can honestly say that my doctor explained to me that such a drastic pre-surgery diet was not necessary. My BMI is only 37 so that may have had something to do with it but he said that surgeons are to lazy to explain that it's the carbohydrates that your body is filtering through the liver and causing it to swell so they just say "do what I tell you". He advised a one week pre-op diet of very low carbohydrate, nutritious foods, not just Protein Shakes. For all of those who are thinking whoaaaaa that sounds crazy? He's a Center of Excellence facility.