Central Heating May Be Making Us Fat

Americans like to crank up the heat in the winter — and some scientists think it’s making us fat. Turn down the thermostat, they say, and you might lose a few pounds.
The link between ambient temperature and weight is not completely far-fetched. When we’re exposed to extreme cold, we shiver, an involuntary reaction that makes our skeletal muscles contract to generate heat, burning extra calories in the process.
And even in mildly cold conditions, like in a chilly room with the thermostat turned down to the lower 60s, people generate extra heat without shivering. The process, called non-shivering thermogenesis, may involve a substance called brown fat that adults carry in certain areas, like the upper back and side of the neck. Unlike regular fat, which stores excess energy and calories, brown fat acts like an internal furnace that consumes lots of calories, but it has to be activated first — and cold temperatures do that.

http://well.blogs.nytimes.com/2011/01/26/central-heating-may-be-making-us-fat/