Multicomponent Models of Body Composition: An Overview

Abstract

This chapter will examine concepts related to a category of body composition methods generally referred to as multicomponent models. Additional details on specific model development are presented in earlier reports (Heymsfield 1990, 1991, 1996, Wang 1995). A component or “compartment” in body research is one of 35–40 discrete clearly defined atomic, molecular, cellular, or tissue-system level entities, as shown in Figure 3.1 (Wang 1992). The sum of all components at each level of body composition is equivalent to body weight. For example, at the molecular level

• (1) Body Weight = Fat + Water + Protein + Glycogen + Minerals

  • Multicomponent models (Table 3.1) consist of three or more components at the same body composition level. Level models, in turn, are the cornerstone of multicomponent model development. An example is the classic three-component model at the molecular level of Siri (1961)

• (2) Body Weight = Fat + Water + Fat-free solids

  • The origin of multicomponent models dates back at least five decades, and many early models remain in use today with little modification from their original early counterparts. Some examples of early influential models are summarized in Table 3.2. The list is not exhaustive, but it is intended to demonstrate the broad array and early development of multicomponent models.