Kraft, the biggest food manufacturer in the United States, is to cut the size of portions, change some recipes and encourage healthier lifestyles in an effort to combat obesity.

The company, which makes Dairylea Cheese, Ritz crackers, Philadelphia spread, Toblerone and many other products, says it is promoting healthier eating - but admits it is also worried about lawsuits. One lawsuit was filed earlier this year that sought to ban Kraft's popular Oreo biscuits on the grounds they contain an ingredient that clogs arteries and "reduces human life". Kraft says the suit is baseless.

"We are making these commitments first and foremost because we think it is the right thing to do," said Mr Michael Mudd, a spokesman for the company.

"If it also discourages a plaintiff's lawyer or unfair legislation, that's just fine with us." The company plans to provide clearer nutrition labelling for its products, so customers know more about what they are buying.

As well as cutting portion sizes in its single-serving snack packs, Kraft will also eliminate marketing campaigns in American schools.