That adult humans possess brown fat is now accepted — but is the brown fat metabolically active? Does human brown fat actually combust fat to release heat? In this issue of the JCI, Ouellet et al. demonstrate that metabolism in brown fat really is increased when adult humans are exposed to cold. This boosts the possibility that calorie combustion in brown fat may be of significance for our metabolism and, correspondingly, that the absence of brown fat may increase our proneness to obesity — provided that brown fat becomes activated not only by cold but also through food-related stimuli.
Barbara Cannon, Jan Nedergaard
Location and control of brown adipose tissue in adult humans.
Brown adipose tissue (BAT) is mainly found in depots localized below the clavicles and in the neck (but amount and shape may vary considerably). The activity of the tissue is regulated from the brain, based on the need for heat for body temperature control (as investigated here by Ouellet et al.; ref.