Pre-Op Protein Shake Diet Question

I am currently on Day 5 of my Pre-Op Protein Shake diet, and I'm drinking the Medifast 70 Shakes and each shake has 14 grams of protein in it. I was wondering if anyone knows what is the MIMIMUM amount of shakes you need to drink in order to get the protein your body needs? These things are nasty and I'd rather not take 6 a day if I don't have to.. I called my surgeons office with this question and they  have yet to call me back!