I am in Day 4 of my 2 week preop diet. I feel tired a lot and seem to have a mild headache constantly. I am dropping about a pound a day which is nice. My diet is two meal with 4 oz of protein (meat or low fat dairy) and low carb veggies and two protein shakes (low carb, with 20 g protein). There are times when I have second thoughts, especially when I talk to people that have know people that gained the weight back, but I have to keep thinking about the reasons I am doing this and take it one day at a time.