 In response to the criticisms of the original thrifty genotype theory, several new ideas have been proposed for explaining the evolutionary bases of obesity and related diseases.The "thrifty epigenomic hypothesis" is a combination of the thrifty phenotype and thrifty genotype hypotheses.While it argues that there is an ancient, canalized (genetically coded) physiological system for being "thrifty", the hypothesis argues that an individual's disease risk is primarily determined by epigenetic events.