The final period of evolutionary history considered here is that of anatomically modern humans. The aim of reconstructing this part of evolutionary history is therefore to address within-species variability, and also to explore the extent to which contemporary variability in adiposity may be attributed to genetic or non-genetic mechanisms.

A combination of fossil, genetic and archaeological evidence indicates a relatively recent origin of modern humans in Africa (Lahr and Foley 1994; Lahr and Foley 1998). However, caution is required when interpreting this speciation in relation to the source of modern human genetic variability.

Reconstructions based on mitochondrial DNA suggested a common ancestor of contemporary humans from between 200–150,000 years ago (Cann et al. 1987; Harpending and Rogers 2000), while the earliest known fossils similarly date from 200–120,000 years ago (White et al. 2003; McDougall et al. 2005). However, this relatively simple model is not supported by polymorphism data from the X chromosome and autosomes (Garrigan and Hammer 2006). Modelling the evolutionary history of the human genome remains a challenging task, with the theoretical assumptions utilised (e.g. relative stability in population size) contributing to the inferences, and in the future, more sophisticated models are likely to improve clarity (Garrigan and Hammer 2006). At present, the most plausible genetic model indicates a degree of admixture between archaic and modern human populations within Africa, allowing genetic variability within Homo erectus to pass into early modern humans (Garrigan and Hammer 2006).