Colder temperatures can induce a massive calorie burn.

    Recently, there is research concerning ways of burning efficiently calories. One potential method is low temperatures. According to Trends in Endocrinology and Metabolism, the optimal temperature for burning calories in fit individuals is 19 degrees Celsius. This occurs due to brown fat composition that warms the body by burning energy to generate heat. 

    The team of Dutch scientists that examine how heat production via brown fat occurs state that energy can be enhanced 30%. An extended period of time exposure to low temperatures can considerably aid in the burn of calories. When the body is exposed to cold temperatures it actually responds to the corresponding conditions by increasing the number of brown fat cells. Brown adipocytes behave differently from the white fat cells as they burn fat at a higher rate compared to the white ones that are responsible mostly with storage of fat.

    Brown fat cells experience a wide accumulation around the upper torso and the neck. A Japanese study that was published in the Journal of Clinical Investigation showed that people who spend at least two hours in mild cold temperatures over a period of six weeks burned significantly and efficiently more calories than people who spent their time in warmer temperatures. 

http://www.naturalnews.com/043701_colder_temperatures_calorie_burn_brown_fat_tissue.html