Could the genetics have remained more or less the same while what people do has changed significantly?
Until the industrial revolution, all work - in the home and for employment - was accomplished with manual labor. Occasionally supplemented with animals, such as horses and oxen. That is how humans evolved, basically to be laborers. From hunting and gathering, to farming, and even skilled trades, almost all work was physical.
The industrial revolution provided significant increases in productivity, but the work remained mainly physical.
But in the US over the last half century, work has shifted from physical to mental. Services, rather than manufacturing, are the large part of todays economy. While some services involve physical activity, many don’t.
It strikes me that the increase in obesity lines up fairly well with the shift from manufacturing to services.
It would make sense, then, that our bodies - evolved to crave high energy food sources like fats and sugars - tend to store that excess energy as fat when we are not sufficiently active. And with manual labor falling as a source of daily exercise, it’s no wonder that the population is getting heavier on average.
—Peter <== who still believes that individual genetics plays a role in how individuals respond to the lack of manual labor as a form of daily exercise.



