Weight loss by increasing energy consumption and thermogenesis

Obesity is caused by a chronic imbalance between energy intake and energy expenditure. The increasing incidence of obesity over the last years is partly caused by the decreased physical activity following industrialization. Weight reduction can be achieved by decreasing energy intake and increasing energy expenditure. The fat loss induced by physical activity, however, is relatively small. Exercise helps to prevent the otherwise inevitable loss of muscle during caloric restriction. Due to the low success rate of conventional weight loss programs, the development of drugs to increase thermogenesis is subject to worldwide research. While in animal experiments stimulation of beta-3 adrenergic receptors leads to a significant weight loss, in humans these drugs fail to stimulate energy expenditure probably due to the lack of significant amounts of brown adipose tissue. The recently identified uncoupling proteins (UCP) 2 and 3 dissipate the protone gradient, thereby releasing stored energy as heat. These proteins might therefore act as potential targets for antiobesity drugs.