Weight training and excercise vs little or no exercise

I have been looking at a lot of before and after pictures on here and they are awesome. One thing that jumps off the page at me is the folks that resumed or started weight training after surgery are just amazing looking! I understand that is not for everyone for various reasons, just an observation. I am half way thru my liquid diet and have my surgery on Tuesday 2/23. The first 2 days on the liquid diet really sucked. Today , day 4 ,has not been so bad. I am thinking that last day before surgey may not be as bad as I anticipated. Honestly at this point I think I can just drink water and eat jello. I have not had any popcycles yet so I may throw those in on tht last day. Anyway, I am hoping I can get in the gym when my surgeon says it is ok and get after it. Good luck to everyone and continued success.