A closer look
Brown adipose tissue is a specialized type of body fat that burns regular white fat calories to generate massive amounts of heat, acting like an internal furnace rather than a passive storage unit for the extra pizza you ate last weekend, and while babies are born with large amounts of this miraculous metabolic tissue to keep them from freezing, adults steadily lose it as they age, mostly because we invented central heating and cozy sweaters, so if you want to activate whatever pitiful scraps of brown fat you have left to boost your metabolism, science suggests you have to subject yourself to freezing cold showers and shivering, turning weight loss into a miserable exercise in self-inflicted hypothermia rather than just going to the gym
