What Doesn't Kill Us

by Scott Carney

Every human alive today lives in a cocoon of consistency: an eternal summer. “We’re overlit, overfed, and overstimulated, and in terms of how long we’ve been on Earth, that’s all new,” he says to me while summer is settling in Alabama. We’re missing out on what he calls “metabolic winter,” a time when the body adjusts to discomfort and scarcity between times of plenty. As he writes in his opus article on the subject, “Our 7-million-year evolutionary path was dominated by two seasonal challenges—calorie scarcity and mild cold stress. In the last 0.9 inches of our evolutionary path we solved both.” The inevitable result of losing seasonal variation is obesity and chronic disease. As proof, he doesn’t point only to the population of his home state, which ranks at #5 of the most obese states in the nation, but also to the fact that our pets are fat, too. “The only two animals in the world that suffer chronic obesity are humans and the pets we keep at home,” he says. “There’s a connection.” The key to fixing the problem, according to Cronise, is to artificially reintroduce seasons back into our lives. Drawing on the growing literature on brown fat and metabolic analysis, he prescribed himself daily hour-long walks in sub-60 degree temperatures along with moderate exercise and calorie restriction. In the course of just 6 months, from June to November, he dropped almost 40 pounds.