Two things come to mind.

Yes, ideally, it's 'healthier' if we have less accumulation and are smaller people. But until about 150 years ago it was considered poor form if your woman was thin. It was a societal trigger that people saw you as either impoverished or didn't do with your money efficiently. If your woman was 'Rubenesque', you were seen as a good man because you made enough cash to feed your woman well. Your woman's figure was a direct reflection of your honor as a man.

The other thing that comes to mind is the female friends I've had that have been heavy and then became thin, still act as though they're large. They excuse themselves if they move around someone, even if there's plenty of room and they sit in the middle of a bench seat before they realize they're smaller and can shift to the side. Wow. What does that say about our outsides not matching the mindset it created? Very interesting.