IN YOUR GENES

This week: A desire to be thin THERE has been much debate in recent years about ‘obesity’ genes. But less wellknown is that some people have ‘skinny genes’ which drive them to be thin.

Researchers at the University of Michigan, in the U.S., quizzed 300 sets of twin sisters on how their bodies compared with those of the slim women they saw every day in magazines, films and on television, and how much they wished they looked like those women.

The researchers called such aspirations ‘thin idealisation’. And they found that in identical twins, who have all their genes in common, if one sister wanted to look skinny, the other tended to want to as well. But there was a far bigger difference in the level of ‘thin idealisation’ among sets of fraternal twins (who develop from two separate eggs), who on average share only about half their genes. In their case, one twin was much more likely to want to appear thin. This was true even if the twin sisters lived similar lives and had similar experiences.