 In the decades following the publications of his first paper on the "thrifty genotype" hypothesis, Neel researched the frequency of diabetes and (increasingly) obesity in a number of other populations and sought out observations that might disprove or discount his "thrifty gene" hypothesis.Neel's further investigations cast doubt on the "thrifty genotype" hypothesis.If a propensity to develop diabetes were an evolutionary adaptation, then diabetes would have been a disease of long standing in those populations currently experiencing a high frequency of diabetes.