> When you gain weight, you also increase the muscles needed to carry that weight around.

I can't figure out how relevant that is. From what I've seen of obese people they always struggle with limited mobility, which often only improves with physiotherapy (or other forms of exercises). Sumo wrestlers are huge but can move faster than an equivalent obese person because (I assume) they have stronger muscles due to their regular regimented training and diet. Does this mean they have more muscle mass than fat compared to an equivalent obese person? Does more muscle mass indicate stronger muscles?

Well, based on my DEXA scan from before I started on tirzepatide, if I had dropped to 20% BF with my starting LBM, I would have been in close to the best shape of my life. I certainly have a lot of extra muscle in my legs from carrying my fat ass around.

> Does more muscle mass indicate stronger muscles?

Yes. Strength for specific movements involves CNS adaptation, but if you look at the top tier of powerlifters, ranking them within a weight category by MRI muscle mass would produce basically identical results to their actual rankings.