Burger King fears $2.5bn float will be flame-grilled by health brigade

America's No 2 chain is going to market just as UK sales dip and 'Fast Food Nation' comes to the big screen

Hold the pickles. Up the lettuce. Burger King is to revamp its UK menu to revive sales as the fast-food industry braces itself for a new onslaught by health campaigners this summer.

The number-two burger chain, which changed chief executives last week, is to follow market leader McDonald's down the health-kick route after admitting the UK is a problem area ahead of its $2.5bn (£1.4bn) flotation. The initial public offering aims to raise as much as $600m but Wall Street analysts are nervous - partly because the UK outlets are doing so badly and partly because the burger industry is about to receive a second assault from Eric Schlosser, author of the best-selling Fast Food Nation.

Mr Schlosser's 2001 book revealed in gory detail the nutritional paucity and health risks of junk food, galvanising opposition to the industry.

Now Mr Schlosser is promising a transatlantic tour to promote a children's version called Chew on This. And executives at McDonald's and Burger King are nervously awaiting the premiere of a fictionalised film version of Fast Food Nation, which could be ready in time for next month's Cannes Film Festival.

McDonald's is considering dusting off a firefighting advertising strategy last used when the film Super Size Me was in cinemas in 2004. It ran full-page newspaper ads telling customers that it was introducing healthier products and that it agreed its burgers and fries should not be eaten to excess.

The company said yesterday that the new Fast Food Nation projects were "very much on the radar". A spokesman said: "While we have not seen the book, our responsibility is to tell the real McDonald's story based on the facts, and the facts are on our side. The McDonald's family will vigorously communicate this information to correct any misrepresentations about our restaurants, our people or our values."

The two chains are particularly concerned because both the new book and film are doing precisely what critics accuse the fast-food industry of doing: targeting kids.

A publicist for Mr Schlosser said that Chew on This was aimed at educating children about how their favourite foods are made: "It will concentrate on poultry because children all seem to be eating chicken nuggets and fries. Mr Schlosser will be doing a big tour of Britain when the book is published on 25 May."

The Fast Food Nation film boasts an ensemble cast including Ethan Hawke, Kris Kristofferson and the pop star Avril Lavigne. It will tell the story of a group of teenagers who work in the industry.

Burger King's private equity owners - Texas Pacific, Bain Capital and Goldman Sachs - plan to sell $400m to $600m of shares, following on from recent successful IPOs for other fast-food chains, including Chipotle and Tim Hortons.

However, Burger King's own prospectus warns of the risks of negative publicity and a gathering legal storm against the junk-food industry fuelled by just such exposés as Fast Food Nation and Super Size Me. It said that it expects further class action lawsuits alleging that the industry failed to disclose the health risks associated with high-fat foods and targeted its marketing at children in a way that encouraged obesity.

In the UK, Burger King said it was losing market share to healthier food outlets. In its regulatory filings, it revealed: "Our business faces challenges due to franchisee financial distress, a negative brand image resulting from concerns about obesity and food-borne illness, high labour and real estate costs and increased competition from bakeries and other new entrants that are diversifying into healthier options in response to nutritional concerns.

"We plan to address these challenges in the UK by improving operations and the image of our restaurants, filling menu gaps to more closely match consumer tastes and focusing on value offerings to drive traffic."