The prepubertal fat spurt seen in mid-childhood coincides with the beginning of adrenarche and is associated with rising serum levels of insulin and insulin-like growth factor-I. As the adrenal cortex expresses receptors for these anabolic peptides, implying that the nutritional status is communicated to the adrenal gland, we hypothesized that nutritional status may be causally involved in the regulation of adrenal androgen secretion. To test this hypothesis, anthropometric indices of the nutritional status and 24-h urinary excretion rates of dehydroepiandrosterone sulfate (DHEAS) were studied longitudinally (during observation periods of at least 4 years) in healthy normal-weight prepubertal and pubertal children. Increases in urinary DHEAS excretion proved to be significantly elevated during periods of individual highest rises in body mass index. These findings provide the first in vivo evidence that a change in nutritional status is an important physiological regulator of adrenarche.