Adverts promoting negative body images will be banned across the Transport for London (TfL) network from next month.
As part of his mayoral election manifesto Sadiq Khan pledged to ban adverts promoting "unhealthy or unrealistic" body images.
The advertising watchdog received 378 complaints in 2015 about a weight-loss advert that asked customers if they were "beach body ready?"
Mr Khan has now asked TfL to set up its own advertising steering group.
The Protein World "beach body ready" promotional posters were defaced in Tube stations and a petition was started calling for the adverts to be banned, however the Advertising Standards Agency (ASA) watchdog later ruled the advert depicting a bikini-clad female model was neither offensive nor irresponsible.
The steering group will advise TfL's advertising partners and stakeholders of the mayor's new policy and will ensure adverts continue to adhere to the regulations set out by the ASA.
Mr Khan 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."
Graeme Craig, TfL commercial development director, said: "Advertising on our network is unlike TV, online and print media.
"Our customers cannot simply switch off or turn a page if an advertisement offends or upsets them and we have a duty to ensure the copy we carry reflects that unique environment."
Previously, the eating disorders charity Beat said while it recognised advertising and media could not cause eating disorders it was aware of how toxic images could be to an individual.
On the BBC London Facebook page many people were quick to praise the mayor's initiative. Magdalena Michalik who lives in Greenwich said: "Please ban it. I don't want my children to look at it!" but others warned it was the start of the "Islamification" of London and said the mayor was adopting this policy because of his religious values.
Sharene Kirchler said: "What happened to free speech? What happened to not being offended by everything. Why is it a matter of state to decide when something so subjective is to be allowed or not?"
The deputy mayor for transport Val Shawcross said the policy was not meant as a "moral judgement", rather the mayor's office was working with the advertising industry to ensure images were not used that were potentially harmful to young people's mental health and how they viewed themselves.