ACTIVITY, CALORIE INTAKE, FAT STORAGE, AND THE ENERGY BALANCE OF INFANTS

Abstract

Activity has long been known to be a major factor in the energy balance of moving organisms. Recently, the relative inactivity of obese individuals and the hyperactivity of thin individuals have received much attention. A study of the relationships of activity, growth, fat storage, and calorie intake of 31 infants living under normal home environmental conditions suggests that the unusually fat and the unusually thin infant may have, respectively, a smaller and larger number of active cells and, therefore, lower and higher BMR's per unit of body mass than the average individual. This would seem to confirm the theory that BMR is a function of inherent mitochondrial activity rather than of body size or shape.