>>some of those countries ascribe social status to those of higher weights

I think just Tonga (also true for Ghana, but I don't think it was high on that list).

Personally, I think the issue is a combination of a suddenly obesogenic environment with a population not adapted plus the prevalence of manufactured foods, with a side of carbs/sugars replacing fats.

Speaking of not being adapted, there's a prevalent SNP (the FTO 'gene') that makes it particularly hard to stop eating when food is available (AKA 'hyperphagic'). I have it, too; I found it easier to swim a mile or more daily than limit input (all non-manufactured foods, BTW). Now that swimming is out (pandemic), I have a problem. Sigh...