For more than 30 years, the Centers for Disease Control and Prevention has been watching Americans' weight. And their height. In that time, it's observed a steady increase in the average body mass index, and with it, the country's obesity rates.
Over at Flowing Data, Nathan Yau has organized this trend into the handy set of graphics you see above. The maps here visualize the steady rise in the prevalence of adult obesity by turning from green, used to indicate obesity rates of less than 20 percent, to purple, for rates higher than 20 percent.
Most articles on the so-called "obesity epidemic" use broad-strokes statistics to describe the issue, as in: "about 38 percent of American adults were obese in 2013 and 2014, up from 35 percent in 2011 and 2012," from The New York Times. Yau's infographic breaks down the numbers by state. Strikingly, the states appear as a grid of equal-sized squares—a mapping strategy that Yau borrowed from FiveThirtyEight. "When you size by geographic area, the bigger states inevitably get more visual attention," he says. Now, with the map's 8-bit looks, all states have equal representation. It won't change the appearance of overarching trends, but it's a helpful distortion if you want to isolate patterns happening in individual states.
