ABSTRACT
Genetic epidemiology has been helpful in defining the magnitude of the familial risk and the genetic contribution to obesity in a population perspective. The level of heritability has been considered in a large number of twin, adoption and family studies, and the estimates vary considerably. However, serious doubts have been raised in many quarters concerning not only high heritability values for obesity phenotypes but even moderate levels, for instance in the range of 30% to 60%, in light of the recent dramatic increase in the prevalence of excess weight around the world. It should be by now clear that the debate has shifted from the population estimates of the genetic risks to the actual genes and mutations predisposing or causing obesity and related diseases. This does not mean that research on population genetic issues pertaining to obesity should not be encouraged. We still have a lot more to learn in these areas. But the field needs to move on to more sophisticated designs and to research paradigms that have the statistical power to address fundamental population genetic questions.
