Actually, to add to part of my previous discussion - some years back, I was helping my wife research a paper on childhood obesity. I found a set of maps chronicling the problem across the United States, with darkest areas showing the highest levels, lightest, the smallest levels.
NOT surprisingly to me at the time - the highest levels of CHILDHOOD obesity were centered in the poor South - Mississippi, Louisiana, Alabama and Arkansas, with mostly lightening areas around the tips and lightest areas in the regions furthest away, namely, the Pacific Coast, the MidAtlantic, Northern Plains and New England. It was almost - but not precisely - a dark area surrounded by increasingly light areas in direct proportion to DISTANCE. Strange.
Since obese children have a high tendency to become obese adults, who tend to raise obese children, I expected the dark areas to get worse over time. It did. As I layered the maps, the poor South got a little worse every year.
But I noticed something also that was strange. So did the regions around it. I know as a nation we've been getting fatter, but the pattern continued so after several years, the regions around the poor South were as dark as THEY were originally. If you watched it on continuous loop, it looked something like paint dropping on a spot and slowly filling up a lighter region, radiating out from one spot.
It occurred to me that something ELSE exactly resembles this pattern.
Disease. A virus. Any other pattern you track over time with a colored demographic map will show different kinds of patterns - gun violence - drug use - cellphone ownership - job growth - if you look at maps fluctuating while looking at these kinds of things, they don't show a single dramatic pattern. But this DID.
I'm not positing some conjecture that obesity is caused by disease. But it may play a factor. Many years ago, it was almost universally accepted that stomach ulcers were CAUSED by stress. No. They are exacerbated by stress. They are caused by a pathogen, which has been identified.
I still wonder this, because I've looked at data for other countries - and some of that pattern is starting. United Kingdom, for example.