Obese Americans seeking compensation from a US food manufacturer have caused concern in the food and restaurant business.

A $50 million class-action lawsuit has been launched against Robert's American Gourmet Foods, after consumer Meredith Berkman noticed the fat content on their low-fat puffed rice snack Pirate's Booty had more than doubled.

Berkman had given the product to her two-year-old daughter, and was alarmed the so-called healthy snack was on a par with junk food.

The civil action is seeking damages for consumers who have piled on the pounds because of mislabelled fat content in foods. Berkman is seeking $50 million for 'emotional distress and nutritional damage.' She said: 'To me this is about truth in labelling, which can be a life-and-death issue. I have always said that if we win any damages they will go to charity.' The food manufacturer's have withdrawn Pirate's Booty but have not responded to the suit, and refused to give comment.

Mike Burita, of the Centre for Consumer Freedom, which represents the food and restaurant industry, fears this will spark a new spate of lawsuits against food manufacturers which could rival those against tobacco companies.

'These actions are the precursors of things to come', he said.