[Finnucane]

The expansion of ranching and farming in the great plains of the Americas was sufficiently bountiful to lead to the first 'health food' crazes of the early 20th century--more people had enough to eat, and increasing automation was already reducing labor. So the roots of our current problem were already being planted, as it were. But in the last 30-40 years, there's been a noticeable uptick in average caloric consumption, even more reduced activity, and more of those calories (at least in the US) coming from processed foods with ever-larger quantities of sugar.