fatigue while at pre-op classes

When I went to my Pre-Op class and testing I got really weak. My question is "Is the Liquid diet the cause? or is there another issue?".

The liquid diet kicked my butt. I thought I was going to be able to work all week and I couldn't I had to take off Friday because I could not take it anymore. I felt so weak. You will feel like that for a while after surgery too. I had VSG on 7/20/15 and am still not feeling back to normal strength. But keep going. It is worth it. Think of the long term goal.