Legislation designed to prevent slave smuggling after 1807 created an extra-ordinary set of documents identifying slaves transported in the coastwise trade by name, age, sex height and colour. Slaves fell below the first or second centile of modern height standards as children but recovered during and after adolescence to exceed the 25th centile as adults. This profile differs remarkably from other populations. Poor pre-natal care, early weaning, food supplements that were nutritionally poor and often contaminated, and a heavy disease load thwarted growth during childhood, but the diet improved substantially when young adolescents entered the labour force. The results show that humans have remarkable capacity for catch-up growth.