Obesity genes probably didn't evolve to help us survive famine

physorg |  Genes that helped our ancestors store fat in times of famine may have been useful, but whether they cursed future generations with a predisposition toward obesity is a little more controversial. This popular "thrifty gene hypothesis" has had its critics, but with a study published September 22 in Cell Metabolism, there is now evidence that nearly all the common obesity-related genes show no properties of traits that evolved because they provide an adaptive advantage.

"This is probably the hardest evidence so far against the thrifty gene hypothesis—our ambition here is for people to entertain a wider range of ideas about where the genetic basis of complex diseases, like obesity, comes from," says John Speakman, a biologist at the Chinese Academy of Sciences Institute of Genetics and Developmental Biology in Beijing, who co-authored the piece with Guanlin Wang, one of his PhD students at the Chinese Academy of Sciences. "The process of evolution is a lot more complex than just the spread of favorable traits by natural selection, and the thrifty gene is like an emblem of this older way of thinking about evolutionary aspects of medicine."