Earlier quoted context omitted.
The side effect of drastic muscle loss isn't quickly reversible though. Because muscle is about 3x as expensive to maintain as fat, unless you are on some major strength training to maintain, muscle is the very first thing that your body gets rid of when losing weight. So now you are off the GLP-1. But you also have to eat fewer calories to maintain a calorie deficit because you no longer have all that calorie burnin…
It doesn’t have to be a foregone conclusion that GLP-1 causes muscle loss though. The primary reason for the muscle loss is the reduction in calories and protein intake. If you want to keep most of your muscle mass you can just make sure you keep up with your daily caloric and protein needs.
We have to do the strength training. "Use it, or lose it".