Can Staying Warm Make You Fat?

Rising indoor temperatures may, in part, account for rising obesity rates in the United States and the United Kingdom, according to a new study from University College London.

The reduced exposure to cold temperatures might minimize the need for energy expenditure to keep warm and lower the body's ability to produce heat, according to researchers.

The paper addresses the role of brown adipose tissue (brown fat) in human heat production. Unlike white fat, brown fat can burn energy to create heat. Exposure to cold is thought to trigger brown fat development. Increased time spent in milder temperatures may lead to a loss of brown fat, and thus, less ability to burn energy.

The study correlates evidence for increases in winter indoor temperatures with weight gain by suggesting more exposure to seasonal cold could help regulate energy balance and body weight. The study combines existing evidence indicating winter indoor temps have increased over the past few decades with figures that suggest seasonal cold exposure is decreasing. Simply put, we are spending more time exposed to milder temperatures.

Almost 35 percent of the American population is considered obese (body mass index of 30 or greater) or overweight (BMI of 25 or greater).