Body Mass Index: Is It The Ideal Universal Weight For Height Index?

The human body is composed of two broad compartments: (i) active tissue mass (lean body mass or fatfree mass) and (ii) the fat mass which is the principal store of energy in the body. In steady state, an individual will maintain his body weight when the input of food energy is equal to the output of energy. Under these conditions, any change in body weight indicates a change in energy balance and, most probably, a change in fat (or energy) stores. Thus body weight is a proxy for steady state as well as reflecting the energy stores of the individual.