Human growth is a dynamic process that involves the complex regulation of tissue development from the moment of conception through adulthood. Fundamental to this process is the need for sufficient substrates required for cellular growth and energy to facilitate growth and development. Thus, when nutrients are sufficiently available and readily absorbed, growth and development occur in a healthy manner. However, when there are interruptions to either nutrient availability, and/or absorption or existing pathologies that influence the endocrine system, growth is disrupted, delayed, or ceases. Central to growth, from conception through early childhood, is the development of tissues that form organs and support normal homeostatic processes, promoting health and decreasing the risk of various diseases. For the majority of children, body tissues are most often grouped with the two major depots of body composition: fat mass (FM) and lean body mass (LBM). Yet these compartments are not constant in terms of their proportion as a child grows, and changes in the relative proportion of one or the other can create a condition in which “healthy” growth is altered and the risk of disease increases.