Changes in body composition and homeostatic control of resting energy expenditure during dietary weight loss.

Adaptive thermogenesis (AT) is the mass-independent decrease in energy expenditure (EE) in response to caloric restriction and weight loss. AT becomes manifest throughout all periods of weight loss and persists during subsequent weight maintenance. AT occurs in resting and nonresting energy expenditure as AT REE and AT NREE , respectively. AT REE appears in different phases of weight loss, each with likely different mechanisms. By contrast, during weight maintenance after weight loss, AT NREE exceeds AT REE . Some of the mechanisms of AT are known now and others are not. Future studies on AT will need an appropriate conceptual framework within which to design experiments and interpret results.