As to why our waists are thickening preferentially, there is no decisive answer. Dr. Ford and colleagues speculate in their article about a number of potential explanations. I am inclined to think that a shift toward diets featuring ever more high-glycemic starches and added sugars is among the smoking guns. High glycemic diets trigger elevations of insulin, and among its many effects, insulin favors the deposition of calories around the middle.
And at that point, the plot thickens along with our waistlines. The deposition of those excess calories as fat around our middles, and in particular in our livers, leads directly to insulin resistance, and higher levels of insulin still. That, in turn, fosters more accumulation of centrally distributed fat, and a degenerating spiral ensues that leads to diabetes, and nowhere good
https://www.linkedin.com/pulse/article/20140918004416-23027997-thicker-middles-skulls-to-match?trk=nus-cha-roll-art-title