There is a correlation between elevation and obesity.

Intriguingly, those areas in which less than a quarter of the population is obese map almost exactly onto the more mountainous regions of the country—the Appalachians, the Rockies, and the Sierra Nevada. And, indeed, after controlling for diet, activity level, smoking, demographics, temperature, and urbanisation, Voss and his colleagues found “a four- to five-fold increase in obesity prevalence at low altitude as compared with the highest altitude category.”

To repeat: Americans who live less than five hundred metres above sea level are more than five times as likely to be obese as their counterparts who live at or above 3,000 metres — even when diet, physical activity, and socio-economic status are all taken into account. Mountain-dwelling Americans, Voss found, weigh in a full 2.4 points lower on the Body Mass Index, on average, than their lowland compatriots.

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