Thrifty Gene

The "thrifty gene hypothesis" was proposed in 1962 and stated that poor fetal and infant growth, combined with existence of Type II Diabetes, would cause permanent glucose metabolism problems.  It was believed that this genotype would confer an advantage in hunter gatherer societies where such individuals would gain a lot of weight in times of food abundance, but still be able to survive during scarcer times.  This recent article in the American Journal of Human Genetics describes a study which explored positive selection for loci known to be associated with Type II Diabetes.  All data was gathered form previously published GWAs.  They conclude that past positive selection was NOT a driving force in prevalence of Type II Diabetes in the current population.

http://www.cell.com/AJHG/abstract/S0002-9297(13)00580-6