Comment by fallingsquirrel

Considering:

- a century ago a greater percentage of people were "normal" weight

- human physiology has not changed much over the past century

- our current definitions of overweight/obese correlate with negative health outcomes

I think the classification is largely correct even if you can haggle over some of the smaller details.

(EDIT: That said, people shouldn't be downvoting you just for asking the question, sorry that happened)