I know I benefited from "newbie gains" since I hadn't lifted seriously in ~20 years.

This is honest and important context. The lean mass gain you're seeing is partly muscle memory (satellite cell-mediated re-growth of previously trained fibers) and partly true newbie gains. A trained individual in the same situation would not see 5 lbs of lean gain during a 40-lb weight loss.

But here's the thing: most people starting GLP-1 therapy AREN'T trained. So your results ARE representative of what an untrained or detrained person can achieve if they commit to resistance training from day one. That's the message worth amplifying.

Those deadlift numbers at 55... respect. I'm 34 and can barely pull 200. Time to stop making excuses.

Ha, thanks. And honestly, the best part isn't the numbers on the bar — it's how I FEEL. I move differently. I stand up straighter. My lower back doesn't ache anymore. I carried all the groceries in one trip last week and my wife looked at me like I was showing off (I was). At 55, I feel physically better than I did at 40. That's not an exaggeration.