Humans are now so prosperous that we are dying of having too much food. A fate our ancestors could have only dreamed of.

This is fantastic for me - the fatter everyone else is, the more attractive I become by simply being not-fat and eating vegetables. Classic win-lose.

Tangent; if there was a nuclear war and subsequent global famine, would the obesity epidemic turn out to be a blessing, allowing more people to survive the initial winter?

Obese isn't a term defined by some quantitative health break-point, or empirical health outcomes, it's an arbitrary threshold established by the guy that invented BMI at a conspicuously nice round number. The term is practically useless for anything more substantial than shame, scare-mongering, and the denial of health care, but insurance companies and the beauty, clothing, wellness, fitness, and dietary industry derive vast amounts of profit from its proliferation, and people to whom it doesn't apply derive some comfort and a sense of superiority from it, and so it remains in common use in spite of, rather than according to, best medical practices.