I am used to performing surgery on patients that have not done any pre-operatory diet mainly because many of them can’t follow any kind of diet and by asking for one just increases their stress before surgery.
Long term carbohydrates and fat diets will turn to storage and infiltration of fat into the hepatic cells. Under this condition, the liver total mass will be progressively enlarged to what’s called pre-cirrhotic stage. By this, fat infiltration of the liver and on patients, the liver will remain enlarged during the lapband Surgery, the Gastric sleeve or the Gastric bypass and the working surgical area turns into a tiny space, reduced for errors in placing the instruments in the right position.
Because there is less room to work with also makes it very difficult to see and recognize the structures, to have enough space to do the right sutures and perform a safely procedure unless the surgeon has enough experience to handle these kinds of situations and has the right bariatric instruments to work with.
We don’t know for sure how much the total liver mass will be reduced by one or two weeks with pre op-diet. My personal belief is that will not shrink too much to make a difference and that the surgeon should be able to adapt to all situations.