Pediatric Nutrition in Practice

2 Michaelsen

0.9–1.1 kg, respectively. Then, growth velocity

declines until the pubertal growth spurt, which is

earlier in girls than in boys ( fig. 2 ).

Different organs grow at very various rates

( fig. 3 ). The relative weight of lymphoid tissue is

greater in children than in adults and the size of

the thymus peaks by 4–6 months of age and then

decreases [2]. The brain, and thereby head cir-

cumference, grows mainly during the first 2 years

of life, with the head circumference reaching

about 80% of the adult values by 2 years. Body fat

mass, expressed as percent total body mass, in-

creases from birth to the age of about 6–9 months,

then decreases until the age of about 5–6 years,

followed by an increase (so-called ‘adiposity re-

bound’). These changes are ref lected in reference

curves for both BMI and skinfolds ( fig.  4 ). The

adiposity rebound typically occurs by 5–6 years

of age. If this happens earlier, the risk of develop-

ing obesity is increased [3].

19

Puberty (3)

Childhood (2)

Infancy (1)

Fetal growth

Growth hormone

Sex steroids

Combined

1 + 2

1 + 2 + 3

11 15

Age (years)

–1 3 7

200

Height (cm)

180

160

140

120

100

80

60

40

20

0

13579 19

Age (years)

11

Girl

Boy

13 15 17

24

22

20

18

16

14

Linear growth velocity (cm/year)

12

10

8

6

4

2

0

180

160

140

120

100

80

60

40

20

200

0

Size attained in percent of total postnatal growth

Lymphoid

Brain and

head

General

Reproductive

0202 4 6 8 10 12 14 16 18

Age (years)

Fig. 1. The infancy-childhood-puberty growth model by
Karlberg [1].

Fig. 2. Linear growth velocity according to age in girls

and boys. Modified after Tanner et al. [11, 12].

Fig. 3. Relative growth of different organ systems. From

Tanner [13] , with permission.

Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 1–

DOI: 10.1159/