The British capital's first Muslim mayor said: "As the father of two teenage girls, I am extremely concerned about this kind of advertising which can demean people, particularly women, and make them ashamed of their bodies. It is high time it came to an end."
Earlier this week, a campaign for Protein World sparked controversy with its "Are you beach body ready" campaign of posters on the London Underground network and buses.
It sparked outrage on social media, with many calling for such posters depicting extremely skinny models to be banned.
"Nobody should feel pressurised, while they travel on the tube or bus, into unrealistic expectations surrounding their bodies and I want to send a clear message to the advertising industry about this," Khan said yesterday.
Khan has asked Transport for London (TfL), which runs the city's transport system, to set up an advertising steering group to advise relevant partners of the new policy and ensure ads adhere to the UK's Advertising Standards Authority (ASA) regulations.