Dr Aric Sigman claims seeing women on screen who are underweight but perceived as "normal" can be harmful to girls and women.
He said a biological mechanism which showed women become unhappy when bombarded with images of underweight women has been identified in many studies, showing the issue was no longer a psychological or cultural debate but a medical one.
"This is a medical and profound message. It is harmful to British girls and women," he said.
Dr Sigman said brain scans showed there were "strong and immediate" brain changes in healthy women exposed to images of thin and fat females, which could trigger self loathing.
He said a brain mechanism that evolved when women lived in small groups was in overdrive with a "proliferation" of images, not just from models but also by news readers or children's television presenters.