A program scheduled for broadcast Thursday on BBC Channel 4 examines what lurks inside prepared foods, especially premium brands and those labeled as healthy.

Nutritionists said some down-market brands are healthier than the premium ones. For example, Sainsbury "Taste the Difference Cheese and Spinach Macaroni" has almost twice the fat as the supermarket chain's "Basics Macaroni Cheese."

The program also examines breakfast cereals, reporting that Kellogg's All Bran has more salt than potato chips while some brands of muesli contain more fat than pork sausages.

Nutrition groups called for tighter government regulation of food labels. They said British standards give food manufacturers a 20 percent margin of error, but the actual products often exceed even that.

Jeanette Longfield of Sustain, a group that campaigns for better labeling, told The Daily Mail that accurate fat reporting would not be burdensome.

"Fat is one of the things that we most commonly look for because of concerns about obesity and heart disease and so on," she said. "It is not a novel ingredient."