The travel network implemented a ban on adverts showing 'junk foods' - i.e those high in fat, sugar, and salt, last month.
According to TFL, it is up to advertisers - in this case online food delivery company Farmdrop - to make sure any items featured in the images were 'high fat, sugar and salt (HFSS)-compliant'.
Junk food ban
The ban, which came into force on February 25, was described by the Mayor of London as a 'groundbreaking measure to help tackle child obesity in London'.
"Food and drink brands, restaurants, takeaways and delivery services will only be able to place adverts which promote their healthier products, rather than simply publicizing their brands," said an official statement.
"With 30 million journeys made every day on TfL’s network, its advertising sites offer a key opportunity to promote good food and a healthy lifestyle to both children and their family members or carers.
"Our advertising policy requires brands to demonstrate that any food or drink products featured in advertisements running on our network are not high in fat, sugar and salt, unless they have been granted an exception," said TfL.
"In this case, Farmdrop chose not to apply for an exception and our advertising agent worked with them to amend the advertisement."
TfL added that eggs would be allowed.
Farmdrop has created an amended version of the ad which will now run on trains.