We've witnessed a lot of positive change in the past 30 to 40 years. More convenient transportation, more air conditioning, less strenuous jobs, less smoking, less expensive food, etc., etc. All of those changes are cause for celebration. They are, however, also all factors that likely contributed to rising rates of obesity we've witnessed over the past several decades.
Here's what I had to say about it in the Food Police
Now comes this paper from Åsa Ljungvall at Lund University in Sweden providing some further empirical evidence for this phenomenon:
It's tough to know whether this is causation or just correlation, but I do think it represents the tough trade-offs we face in life. We could all be a bit thinner if we lived in North Korea. I doubt many of us would be willing to trade our freedom just to drop a few pounds.