Recent scientific and public excitement about brown adipose tissue (BAT) in humans stems from initially speculative extrapolation from animal experiments described in foregoing papers. Recognition that variations in the activity of the tissue can determine the overall efficiency of energy utilization, strengthened by the demonstration of thermogenic responses to overfeeding, has directed interest towards the possibility that BAT could be of importance in energy balance and the aetiology of obesity in humans, and perhaps more importantly, as a novel route for treatment (Himms-Hagen, 1979; James, 1983).

These suggestions require that BAT should be present and functional in humans, capable not only of regulated heat production to maintain body temperature, but also of physiological stimulation to remove unnecessary energy ingested as food. If BAT is potentially active in adults, then energy wastage might be inducible by therapeutic intervention for the treatment of obesity. Recent work has explored some of the grounds for recent speculation about human BAT thermogenesis, to strengthen the analogies with animal models.