Cold-Activated Brown Adipose Tissue in Healthy Men

The authors of this study measured putative brown-adipose-tissue activity in relation to body composition and energy metabolism, using a standard protocol and integrated positron-emission tomography and computed tomography. Twenty-three of 24 healthy men had detectable levels of activity after cold exposure but not under thermoneutral conditions. Brown-adipose-tissue activity was positively related to resting metabolic rate and was significantly lower in overweight or obese subjects than in lean subjects. The authors measured putative brown-adipose-tissue activity in relation to body composition and energy metabolism. Brown-adipose-tissue activity was positively related to resting metabolic rate and was significantly lower in overweight or obese subjects than in lean subjects. There is evidence that stimulating adaptive thermogenesis, defined as the facultative heat produced in response to cold and diet, might serve as a means of preventing or treating obesity 1 ; thus, it is of interest to understand the mechanisms underlying adaptive thermogenesis. We previously reported that cold-induced thermogenesis in the absence of shivering accounts for an average of 11.8% of the resting metabolic rate, with high individual variation. 2 Individual differences in energy expenditure can have large, long-term effects on body weight. 3 Several prospective studies have shown that a relatively low energy expenditure predicts a gain in body weight. 4 , 5 Hence, . . .