Myself being metabolically very old-fashioned and having experienced the range from BMI 19 to BMI 31 have a general idea what you're talking about ;).

Given an adequate Lean/Fat Mass Ratio which often cannot be seen with the naked eye, even if the body is naked, people are generally healthy in that respect. I would not try to predict any biomarkers and risk factors (except joint degradation) for them or denigrate life styles they exhibit.

Of course there are the clinically obese "human food-feces converters" (yeah, I'm a bad guy) where it is physically impossible an adequate amount of lean mass is buried under those flabby expanses... but i digress. And also, that is a pathological condition and I denounce and reject any prior cynical expressions made.

As a sidenote i might add that, if the economic system demands unrestrained growth, who can blame the lower cast people lacking real opportunities to expand the only thing they have the power to do so? But I digress again... ;).