Britain's advertising watchdog is to investigate ads for a slimming product that sparked outcry on social media this week when they appeared in London's Underground rail network.
The advert for Protein World slimming shakes showed a slim woman in a bikini with the words "Are you beach body ready?"
Many of the posters were defaced following a social media backlash and more than 60,000 people signed a petition to remove them.
The Advertising Standards Authority (ASA) said it had met with Protein World to discuss the advert and was investigating after it received 360 complaints.
"Due to our concerns about a range of health and weight loss claims made in the ad, it can't appear again in its current form," the ASA said on Wednesday.
"We've launched an investigation to establish if it breaks harm-and-offence rules or is socially irresponsible."
Campaigners are to hold a "Taking back the beach" protest on Saturday in London's Hyde Park and have invited people of all body shapes to attend.