Correlation and Causation

Because good science on humans is so hard to do well, we still rely too much on corellation.  The most compelling narrative to be found is scary and simple:  the majority of the diseases of the West are not present in paleolithic cultures; if they are, they are found in much lower numbers.  This has been known for many years, but is only recently being used as a framework to understand what makes humans sick.  What do we do now that we didn't do before the advent of agriculture?  There are many, many factors, and there's no clear cut proof of what the ancestors ate, but the "paleolithic model" is a better far more useful framework than the absurdity on display by the "correlation is causation" crowd, as described below:

..it's no surprise that the relationship between diet and cancer is still largely a matter of educated guesswork--and in many cases, the guesses have turned out to be wrong. Take the much publicized link between high-fat diets and breast cancer, for example. Women who live in Western countries, where high-fat diets are the norm, tend to have high breast-cancer rates. Even more telling: women of Japanese ancestry who live in the U.S. get the disease six times more often than their grandmothers and great-grandmothers in Japan. Yet a huge recent study of 90,000 women has refuted the breast cancer-fat link. Fat has also been suggested as a trigger for colon, prostate and bladder cancers--but there's no hard evidence that cutting fat will reduce your risk for any of these diseases.
Read more: http://www.time.com/time/magazine/article/0,9171,991543,00.html#ixzz1WRuJ0sQF

This is a significant document from a medical doctor documenting the progression of Western disease (but at $85, I won't be buying that soon):  http://www.amazon.com/gp/product/1405197714/ref=s9_simh_gw_p14_d1_g14_i1?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0QSCMCGM5F7TSVD291SJ&pf_rd_t=101&pf_rd_p=470938631&pf_rd_i=507846