In this conversation, Thomas P Seager, PhD, interviews Denis Blondin about the fascinating world of brown fat and its implications for human health. They discuss the recent discoveries surrounding brown fat in adults, the mechanisms of non-shivering thermogenesis, and the role of cold exposure in activating brown fat. The conversation also delves into the relationship between brown fat and insulin sensitivity, the potential for targeting brown fat as a therapeutic approach, and the connections between brown fat, thyroid hormone, and mental health. Throughout the discussion, they emphasize the importance of understanding brown fat's role in metabolism and the benefits of cold exposure for overall health.