Hypermetabolism, cachexia and wasting

Purpose of review Unintentional weight loss complicates many disease processes and is generally a poor prognostic sign. The terms used to describe weight loss (hypermetabolism, cachexia, wasting, catabolism) are often inconsistent. The aim of this review is to define the components of energy expenditure and the terms that describe inappropriate weight loss. Furthermore, these terms will be applied to several common disease entities on the basis of findings from recent studies. Recent findings Significant variation in the literature surrounds the definition of hypermetabolism and which conditions are considered hypermetabolic. For example, the weight loss of HIV wasting syndrome is due to reduced energy intake rather than to increased energy expenditure. Similarly, the primary catabolic hormones do not seem to cause hypermetabolism in isolation but rather require the appropriate hormonal milieu. Summary Clarifying the terminology of energy expenditure and hypermetabolism, and then applying it appropriately to disease states, will allow for optimization of medical therapy and nutritional support.