Minnie size me: Disney bans junk-food ads for kids – with a little help from Michelle

As a global media conglomerate that owes its entire existence to square-eyed children who spend their waking hours glued to a television set, the Walt Disney Company makes an unlikely advocate for the benefits of a healthy lifestyle.

That is exactly where the organisation known in Hollywood as the "Mouse House" now finds itself, however, after announcing a pioneering ban on the promotion of junk food across its array of kids' TV shows, internet sites and radio programmes.

Executives from Disney held a news conference in Washington with the First Lady, Michelle Obama, yesterday morning to outline its plans to become the first major US broadcaster to eliminate from its airwaves advertisements for unhealthy meals, drinks and snacks aimed at children under the age of 12.

The rules stipulate that food products that are advertised on channels such as Disney XD or that sponsor shows on The Disney Channel must comply with nutritional guidelines that place limits on salt, sugar and fat levels, together with overall calories. They will be phased in across the US over the next three years, to comply with existing commercial contracts, and then "gradually rolled out" in other territories, including the UK, according to a spokesman. The firm is also to reduce by 25 per cent the amount of salt in children's meals served at its theme parks, carry a series of "public service" adverts that promote exercise and healthy food, and introduce a range of Disney-themed fruit and vegetable products to be sold in supermarkets.

Disney's move comes days after New York's Mayor, Michael Bloomberg, announced a ban on large servings of soft drinks in the city. Healthy-eating campaigners hope that, together, the shifts indicate that America is finally coming to grips with what they call its "obesity epidemic" – a third of the nation's children are overweight and around 17 per cent are clinically obese.

Ms Obama, who has devoted much of her time as First Lady to campaigning for healthier eating, praised Disney for "doing what no major media company has ever done before in the US". She called its policy a "game-changer" and hopes it will be mirrored by rival media organisations such as Nickelodeon and Discovery Kids.

In recent months, Ms Obama's efforts to promote her signature cause, which has extended to creating a vegetable garden at the White House, have been noisily ridiculed by a small number of mostly right-wing critics. They believe that encouraging children to eat healthily and take more exercise represents an incursion by the Nanny State into the private lives of families.

But Disney's chairman, Robert Iger, told The New York Times that he believes the potential long-term benefits of the move outweigh whatever short-term commercial loss his firm might suffer by turning away advertisers or angering the First Lady's political opponents.

"Companies in a position to help with solutions to childhood obesity should do just that," he said. "This is not altruistic. This is about smart business."

'Health' snacks: What they really contain

Capri-Sun

It comes in a pouch, adorned with a picture of some fruit. But don't be fooled: the biggest ingredient (aside from water) is "high fructose corn syrup", a cheap replacement for sugar referred to as "the devil's candy" by critics.

Kraft Lunchables

The new Disney guidelines stipulate a maximum of 1.1g of saturated fat per 100 calories of food. The Lunchable Deep Dish Pizza – a sort of processed mini-meal – contains almost double that.

Frigo Cheese Heads

Cocooned in layers of plastic, this processed snack trumpets its status as "America's favourite string cheese". It also claims to be "all natural," but if you think that equals healthy, think again: each portion boasts 280mg of sodium, 80mg more than Disney's limit.

Froot Loops

This "sweetened multi-grain cereal" has an ingredient list that begins with sugar, moves swiftly through flour and fat, and ends in a cocktail of food colourings.