Changes in Density of Human Body and its Fat Content with Special References to Age

Abstract

Applying the authors' method of estimating the body density which was reported previously, the human body density of young men from 7 to 22 years old was estimated, and the fat content in the body was calculated by Keys' method.The human body density is low in childhood and increases with growth and attaining the maximum at the age of about 16 or 17 years old, the value remains almost constant or tends to decrease. The body fat content (in percentage of body weight) decreases with age as the body density increases fill about 16 years old, while tends to increase thereafter.It follows that the total fat content in the body increases little by little until 16 years and after 17 years old, it increases remarkablly.From these results, it is concluded that the increase of body weight of young boys who are younger than about 16 or 17 years old, is mainly due to the increase of lean body mass, while the increase of body weight after 17 years old is not only due to both lean body mass but also to the content of fat in the body.

Age‐related pattern of body density and body composition in Japanese males and females, 11 and 18 years of age

“…The underwater weighing method was used for all studies except that of Nagamine (1974), who applied the water displacement method. RV was measured by the closed-circuit approach with helium (Kim, 1993;Watanabe et al, 1993;the present study), by the open circuit approach with nitrogen washed-out (Ikai et al, 1969;Hachisuka et al, 1970;Kitagawa, 1988;Sato, 1978), or by estimation from height (Nagamine, 1974). Hachisuka et al, Kitagawa et al, and Sato measured RV inside the water tank where subjects were in water up to the neck.…”

“…Body composition of Japanese children and young adults as measured by densitometry (underwater weighing) has been reported by several authors (Hachisuka et al, 1970;Nagamine, 1974;Kitagawa, 1988). Most authors delineated the characteristics of body composition of children in specific age groups.…”

“…This is mainly due to difficulties in measuring body density of a sufficiently large sample using the underwater weighing method. Hachisuka et al (1970) reported body density of Japanese males between 7 and 22 years [also shown in a report of the Japanese International Biological Program (Matui, 1975)], but the total number of subjects was only 135 with less than 10 subjects in each age group. There are no data available for Japanese females.…”