The Genie Age
Why 9 to 19
Ten years build most of the adult body. Then the window closes.
Adolescence is the only real growth spurt a body gets after infancy. In roughly ten years a child adds most of their adult height, banks most of their skeleton, and rewires the parts of the brain that handle focus, sleep and stress.
It runs on its own schedule, it is different for every child, and it happens once. Nothing after nineteen reopens it.
Four things this decade decides.
1
Height
Long bones grow at the growth plates near each end. At the close of puberty those plates fuse, and the growing stops. Nothing after that reopens them, which is why the years before it matter so much.
2
Bone
The skeleton banks most of its lifetime mineral density during adolescence. What isn't laid down in this decade isn't laid down later, and it's what the body draws on for the next seventy years.
3
The brain
Wiring and myelination carry on right through the teens, particularly the parts handling focus, planning and stress. This window makes or breaks the stress-bearing capacity, focus, etc.
4
Iron and the cycle
Once periods start, iron demand rises sharply and stays raised. Tiredness in teenage girls is very often iron rather than laziness, and it's easy to check.
A thirteen-year-old is not a small adult.
Per kilo of body weight, requirements during the growth spurt are higher than at any other point in life, and the shape of the requirement is different too. More calcium, because the skeleton is still being built. More iron, because blood volume is expanding and, for girls, because periods have started. More protein, because muscle and organ tissue are being laid down at speed.
Most supplements sold to teenagers are adult formulas at a smaller dose. That gets the arithmetic backwards: a smaller body doing more building work does not need less, it needs different.
What the body is actually asking for.
Protein alone, per day, for an Indian adolescent. It nearly doubles between ten and eighteen.
| Age | Boys | Girls |
|---|---|---|
| 10 to 12 | 31.8 g | 32.8 g |
| 13 to 15 | 44.9 g | 43.2 g |
| 16 to 18 | 55.4 g | 46.2 g |
ICMR-NIN, Nutrient Requirements for Indians, 2020.
What to feed it, from an Indian kitchen.
Food first, always. Most of this is already in the house.
Calcium
Ragi, til, curd, paneer, milk, rajgira, drumstick leaves.
Iron
Gud with chana, palak, bajra, rajma, dates, poha, and liver if the house eats it.
Protein
Dal, egg, curd, paneer, soya, peanuts, sprouts.
Vitamin D
Twenty minutes of morning sun on arms and legs. Fortified milk where the sun isn't reliable.