Muscle weakness?

I am just wondering if anyone of you suffer from muscle weakness while on LL? I have a back problem - for years, even when I was slimmer. Then when I put on weight and going through pregnancy, my back problem almost disappeared. But it was in the past year that my back problem returned and it got worse after I lost weight on LL. Now, my mobility is a bit restricted because of the pain. I also have knee problems due to my weight but now I am so worried because it seems to me that it gets worse when I lose more weight! My husband guessed that it could be muscle weakness that affected my back and knees. You lose fat, you lose muscle as well....

I feel great apart from that and would have loved to be more active, exercise, etc but I can't because of my back! This sucks!!! :cry: