The only time I have to have liquids is 48 hrs before. This last week I had to do i shake in the morning , a sensible lunch and sensible dinner. They suggested lean cuisines or smart ones that didn't contain pasta or potatoes. This week I do 2 shakes and a sensible dinner. I asked him about a liquid diet but he said it wasn't necessary. I had two friends use the same doctor and they were put on liquid diets but their BMI's were higher than mine...that's the only reason I can think of.