In my opinion people are over weight because no one works hard like they used to everything it automated and computer ran.
Most people in the 50's and 60's grow up on a farm or worked on a farm. That's hard manual labor that turned a boy into a man.
We lived a more subsistence life style we depended on cutting wood to heat our homes, we depended on raising our cattle for meat and milk. None of that is easy work, I would know I grew up baling hay, chopping wood and tending to hogs and cattle. This "going to the gym to run on a hamster wheel" for a hour a day isn't doing it.