We learned that genetics could play a bigger role in women’s desire to be thin than societal pressures.

In a study published in the International Journal of Eating Disorders, researchers sought to determine why some women develop ‘thin ideal internalization’ – or an obsession with being thin, and why others do not. 

For the study, 300 sets of female twins aged 12 to 22 were asked how strong their desire was to resemble people they had seen on television, in movies and in magazines.  After compiling their responses, the researchers compared the responses between sets of fraternal twins – who share 50 percent of the same genes – and identical twins – who share 100 percent of the same genes.

The results found that the sets of identical twins had closer levels of thin ideal internalization than the sets of fraternal twins.  Further research found that 43 percent of thin idealization is inherited.