A ban on junk food advertising across London's public transport system will be introduced on February 25.
The capital's mayor Sadiq Khan has confirmed the 'tough action' initiative, which is part of the London Food Strategy to reduce child obesity in the city by 2028.
Promoting sugary drinks, chocolate and burgers will be prohibited across the entire transport network, including the Tube, bus stops and the London Overground.
The restrictions also outlaw goods deemed 'less healthy' by Public Health England, such as salted nuts.
However, fast-food chains will still be allowed to promote their healthier products, such as salads, as long as they are low in fat, salt and sugar.
Speaking of the move's impact on reducing obesity, Mr Khan told the BBC: 'Reducing exposure to junk food advertising has a role to play in this - not just for children, but parents, families and carers who buy food and prepare meals.'
Popular High-Street chains, such as Burger King, KFC and McDonald's, will also be unable to 'outsmart' the campaign by simply advertising their logo.
But promoting unsalted nuts, raisins and sugar-free drinks will be permitted.
However, advertising experts fear the divisive measure could cost Transport for London millions of pounds in lost advertising revenue.
Moreover, Justin Cochrane, chairman of the trade body Outsmart, which represents advertisers, claimed Mr Khan declined to work with the industry on a compromise that would preserve TfL's revenue.
He told MailOnline: 'As a result, it will hit industry revenues and could cost jobs. It will also add more than £125m to TfL's mountain of debts over the next five years.
The Advertising Association has also said the move will have 'little impact on the wider societal issues that drive obesity'.
In a poll of 1,500 Londoners, 82 percent said they backed the proposal, according to City Hall.
London has one of the highest childhood obesity rates in Europe, with almost 40 percent of children aged 10 and 11 being overweight or obese.
This comes after ministers announced plans to push on with initiatives that force all restaurants and takeaways to put calorie labelling on their menus, despite widespread opposition.
The Department of Health said it would help the battle against obesity and type 2 diabetes, and may come into play from March next year.