Objective: To assess the changes in energy intake (EI), food intake volume (FV) and energy density (ED) related to age and gender in a population in the Mediterranean area of Spain, and to determine the different role of FV and ED on the consecution of the adequate EI throughout lifespan. Subjects: One thousand and eighty-eight individuals (1 ± 65 y) randomly selected from the population census. Design: Cross-sectional study in which food intake was quanti®ed by 24 h dietary recall, three non-consecutive days. Height and weight measurements were taken in 885 individuals. Results: EI, FV and ED increased progressively (P`0.001) between 1 ± 2 y and 10 ± 12 y of age in both sexes. At 1 ± 2 y the EI is 5.8 AE 1.5 MJad, FV 1195 AE 275 gad and ED 4.8 AE 0.9 kJag. Between 1 ± 2 and 3 ± 4 y, coinciding with an EI that increased up to 7.2 AE 1.5 MJad, there was an increase in ED up to 6.1 AE 0.8 kJag (P`0.001), while the FV did not vary signi®cantly. At the start of puberty, between 7 ± 9 and 10 ± 12 y, when the EI increased to 9.7 AE 0.9 MJad (P`0.001) in males, the ED rose to 7.1 AE 0.9 kJag (P`0.001) while the FV did not vary signi®cantly. At this age, a signi®cant difference between the genders was observed in the EI (P 0.04), and in the ED (P 0.02) but not, as yet, in the FV. During adulthood, a signi®cant trend towards decrease (P`0.001 in both sexes) was observed in EI and ED. However, FV decreased signi®cantly only in females. Conclusions: The changes in energy intake that were observed with respect to age and gender were accommodated-for by changes in the ED of the diet rather than by variations in food volume intake. Autoregulation of the ED of the diet, suf®cient for energy intake requirement changes, appears to be an essential human capacity for ef®cient nutrition. Sponsorship: This study was funded, in part, by a grant for B Vizmanos from DANONE, Spain.