Were eating habits more refined?
No, they just ate a little less and exercised more.
I recently read that four things we commonly eat today will cause the human body to put on fat: bananas, corn, wheat, and peas.
Of those four items, one in particular has crept into the ingrediants of a huge number of products we eat today - corn. It is the additive corn syrup or corn syrup solids that I suspect is fueling obesity in this nation.