Body weight/height relationship: Exponential solution.

Regression of weight (W) on height (H) in all higher primates is of exponential form W = a · exp(H · b) and is uniform for both nongrowing adults and growing children. Parameter a values are always close to 2.0 and b to 0.02. The exponential equation fits ontogenetic data better than the traditional allometric power curve. The exponential nature of the W/H regression during growth may be explained by mechanisms of cell proliferation: Arithmetic growth of the skeleton at epiphyseal plates and geometric proliferation of many other tissues of the body. Sexual dimorphism and interpopulational differences in a and b values are interpretable: e.g., girls have lower initial weight (lower a values) than boys, and Africans (low b values) grow "slimmer" than Eskimos. The effects of improved environmental conditions can also be described. Children of the same ethnic group have higher a and lower b values when growing in better condition because of higher initial weights, but acquire elongated physiques during growth. Use of exponential W/H relationship as growth standards and for reconstruction of body build in fossil material is postulated.