Fig. 5.

Impact of weight loss on the components of total energy expenditure (TEE). Energy-restricted weight loss impacts every component of energy expenditure. The absolute levels of resting energy expenditure (REE) decline from a loss of metabolic mass and enhanced metabolic efficiency. Nonresting energy expenditure (NREE) declines, unless the level of physical activity and its associated exercise activity thermogenesis (EAT) are substantially increased. This increase must overcome the decline in the TEF that results from lower energy consumption and a decline in nonexercise activity thermogenesis (NEAT) related to loss in overall mass. Increased energetic efficiency of EAT, NEAT, and potentially TEF contribute to the overall decline in NREE.