I saw some research 20 years ago stating that Eskimos had a much larger percentage of brown fat to white. It was thought that if you slept in an artificially cool room, over time you could change some of your white fat to brown, which actually burns calories. I asked if I could put my little brother in the freezer, as a test, but Mom always said “No”.
Climate control is making us fat, lol. Another rationalization for smart meters.
I drink 1.5 gallons of ice cold water per day approx. Numerous studies show that if you drink very cold water versus warmer water you burn more calories over time...can't remember the reason maybe lowering core body temp for a short time and the body reacts??