The thrifty genotype hypothesis has been used to explain high, and rapidly escalating, levels of obesity and diabetes among groups newly introduced to western diets and environments, from South Pacific Islanders,[REF] to Sub Saharan Africans,[REF] to Native Americans in the Southwestern United States,[REF] to Inuit [REF].
As a response to such criticisms, a modified "thrifty" gene hypothesis is that the famines and seasonal shortages of food that occurred only during the agricultural period may have exerted enough pressure to select for "thrifty" genes [REF].