In looking at height through the millennia, Jason Collins came across Robert Fogel’s work on American slaves:
Historians had long insisted that slavery was not only inhuman; it was bad business — hungry, brutalized workers made the poorest of farmers. Fogel and Engerman found nearly the opposite to be true: Southern plantations were almost thirty-five per cent more efficient than Northern farms, their analysis showed. Slavery was a cruel and inhuman system, but more so psychologically than physically: to get the most work from their slaves, planters fed and housed them nearly as well as free Northern farmers could feed and house themselves. …
Steckel decided to verify his mentor’s claims by looking at the slaves’ body measurements. He went through more than ten thousand slave manifests — shipboard records kept by traders in the colonies — until he had the heights of some fifty thousand slaves; then he averaged them out by age and sex. The results were startling: adult slaves, Steckel found, were nearly as tall as free whites, and three to five inches taller than the average Africans of the time.
The height study both redeemed and rebuked “Time on the Cross.” Although the adult slaves were clearly well fed, the children were extremely small and malnourished. (To eat, apparently, they had to be old enough to work.) But Fogel was more than willing to stand corrected.