With two weeks to go to the release of Morgan Spurlock's anti-McDonald's documentary, Supersize Me, the fast-food chain has launched a pre-emptive strike in the UK with an ad campaign in national newspapers.

In the film, Spurlock put on 27 pounds and saw his cholesterol and blood pressure rise after eating nothing but McDonald's hamburgers for a month.

"What may surprise you is how much of the film we agree with," the ad says, before later declaring: "We do agree with ... its core argument, that if you eat too much and do too little, it's bad for you." The ad claims the film is flawed because an average customer would take six years to eat the same amount of burgers as the film-maker ate. It also claims the weight gain was exaggerated because the film-maker cut his physical activity to a bare minimum, and points to its new, "healthier" meal options. McDonald's spokeswoman Amanda Pierce said: "We wanted to ensure there is a balanced debate so people hear our side of the story."

At the Edinburgh Film Festival, Spurlock responded: "McDonald's is a company that is brilliant at publicity and marketing, and what people need to realise is that they only care about your health as long as it's good for business. All of their 'healthy' options are only window dressing around a bigger problem."