Intra-individual variation in energy requirement and its genetic significance

Abstract

It is generally assumed in nutrition studies that the energy requirement of an individual is fixed and that any variation from day to day is negligible relative to variation between individuals of the same age, sex and body weight. However, this assumption does not find support in the available data and on the contrary, the requirement in an individual is found to vary over time. This variation is found to persist even when data are averaged over a week. Further, the requirement follows a stochastic stationary distribution implying that as man advances in time, the genetic entities possessed by him interact with the environment to keep the variance constant. An attempt has been made by the authors to relate the genetic component due to this interaction with the auto regulatory mechanism. It has been found that the strength of this interaction can be measured in terms of the serial correlation coefficient signifying the degree of auto-regulatory mechanism.