http://www.biomedcen.../1471-2458/10/746

Real MEAT here:
Clicking on the 'squiggly icons' at left of many paragraphs, opens a pop-up with many. Interesting. graphs.
Was just going to skim this link, but got sucked in--because it's exemplary sci-grade exposition, sans all-too-common MAN *nix type obfuscatory acronyms.

Hmmm.. maybe the Chinese + Japanese together can improve Murican academic style in such reports?
But the tradition of special-jargon runs deep in Murica.

Seems that B-vit, fortifications in grains, ditto + nicotinimide, used to make meat look RED! etc. loom large in the Whys of these astonishing curves of increased calories/person/day + all the rest:
Hey.. B vitamins were KNOWN to increase appetite, yet for ALL those DECADES ... nobody was NOTICING.

Academic Alzheimers? Attention-span-deficit-Disorder? ... just plain ... ... sloth??
Gotta delve further--thanks for the Econ link; ordinarily MEGO re. formal Sci. Doc. intentionally bland syntax, vocab + style (-NOT).

Love the Econ Inequality / parallel curve suggestion in Comments, (esp. rebuttal to the attempted snark at The Very Thought!)
Intelligence isn't dead in Murica, merely Buried under $Billions of the many Greed- PACS/"Think"-tanks and other
'financial instruments of mental depravity and sociopathic-Greed', daily sanitized by the, what was it..
4? 6?? mega-Corps who own virtually all the mass media, paper/transistors/or whatever form.

Excerpts:

B-vitamin consumption and the prevalence of diabetes and obesity among the US adults: population based ecological study

[... ... ... ...]

Results

The prevalences of diabetes and adult obesity were highly correlated with per capita consumption of niacin, thiamin and riboflavin with a 26-and 10-year lag, respectively (R2 = 0.952, 0.917 and 0.83 for diabetes, respectively, and R2 = 0.964, 0.975 and 0.935 for obesity, respectively). The diabetes prevalence increased with the obesity prevalence with a 16-year lag (R2 = 0.975). The relationships between the diabetes or obesity prevalence and per capita niacin consumption were similar both in different age groups and in male and female populations. The prevalence of adult obesity and diabetes was highly correlated with the grain contribution to niacin (R2 = 0.925 and 0.901, respectively), with a 10-and 26-year lag, respectively. The prevalence of obesity in US adults during 1971-2004 increased in parallel with the increase in carbohydrate consumption with a 10-year lag. The per capita energy and protein consumptions positively correlated with the obesity prevalence with a one-year lag. Moreover, there was an 11-year lag relationship between per capita energy and protein consumption and the consumption of niacin, thiamin and riboflavin (R2 = 0.932, 0.923 and 0.849 for energy, respectively, and R2 = 0.922, 0.878 and 0.787 for protein, respectively).

Conclusions

The present study revealed that the increased prevalence of obesity and diabetes in the US in the past 50 years was closely correlated with the increased daily per capita consumption of niacin, thiamin and riboflavin of with distinct time lags, and suggested that long-term exposure to high level of the B vitamins may be involved in the increasing prevalence of obesity and diabetes. The present findings, together with the evidence that niacin may induce glucose intolerance, insulin resistance and liver injury, imply the possibility that, among the fortified B-vitamins, excess niacin consumption may play a major role in the development of obesity and type 2 diabetes. Since the high level consumption of niacin in the US is mainly due to the implementation of mandatory grain fortification, therefore, it may be of significance to carefully evaluate the long-term safety of food fortification.

These two articles portray the Tip of the iceberg of related incompetent regulations, never reprised for accuracy or efficacy
+ the Gordian Knot of interbred/recursive/obfuscated Special-$$$-Interest staying with a Cosa Nostra [We gots Our Thing, just like the Italians]
soon-Lucrative-habit of the Murican-fodder corporate collective(s) apparently in tandem agreement worldwide:
NEVER actually to TEST the underlying assumptions of 'enrichment' [in a dietary sense; the $$-sense goes without Saying, I wot.]

It can't be Shocking, such a realization: after all, a majority of the 'civilized world™' embarked upon such an excess of nuke proliferations as to
Literally Destroy (the habitability of) the World. By any accidental brain-fart / for all those decades. Ergo,

NOTHING {should} Surprise us. Should it?
I shall try to save a few more cats, next.
We have become, as a species: preposterous :-/

Ed: PS:

In my 1.5 year experimental diet of practically no grains, few carbs, via a then-new Org deriving many (today called, 'pro-biotic') soil-derived substances
--my metabolism appears to have changed--remaining stable even long after discontinuing the rather expensive supplies,
while adding-back small amounts of the usual tasty stuff, only occasional grass-fed beef (say) frequent (non-farmed) salmon (which, fortunately I Like anyway.) Etc.

I was at least 25# above 'good'-weight, and am now at about same weight of best fighting-trim years. And similar energy.
(Natch I claim no prescience re. these particular findings--claim merely to have Noticed the effects of this.. nearly-capricious choice! of an interesting experiment-on-self.)
Which worked in ways I couldn't imagine, let alone 'expect'. I call it, Luck: I thought I'd try that regimen for ~ 6 months maybe.
Sometimes you win (an unknown bet.)