James Hamblin examines research connecting warmth and human metabolism:
[Former NASA materials scientist Ray] Cronise believes that our thinking about the modern plagues of obesity and metabolic disease (like diabetes) has not addressed the fact that most people are rarely cold today. Many of us live almost constantly, year-round, in 70-something-degree environments. And when we are caught somewhere colder than that, most of us quickly put on a sweater or turn up the thermostat. …
Cronise, [Andrew] Bremer, and [Harvard geneticist David] Sinclair propose what they call the “Metabolic Winter” hypothesis: that obesity is only in small part due to lack of exercise, and mostly due to a combination of chronic overnutrition and chronic warmth. Seven million years of human evolution were dominated by two challenges: food scarcity and cold. “In the last 0.9 inches of our evolutionary mile,” they write, pointing to the fundamental lifestyle changes brought about by refrigeration and modern transportation, “we solved them both.” Other species don’t exhibit nearly as much obesity and chronic disease as we warm, overfed humans and our pets do. “Maybe our problem,” they continue, “is that winter never comes.”
The Dish 