Evolutionary origins of the obesity epidemic: natural selection of thrifty genes or genetic drift following predation release?

Abstract

This article challenges Speakman's hypothesis that the modern genetic predisposition to obesity has arisen through random genetic drift in the two million years following predation release. We present evidence in support of the hypothesis that a mixture of famines and seasonal food shortages in the post-agricultural era have exerted natural selection in favour of fat storage; an effect most likely mediated through fertility, rather than viability, selection. We conclude that, far from being time to call off the search, recently developed genetic and bio-informatic methods will soon provide a definitive resolution to this long-standing ‘thrifty gene’ controversy.