US-style calorie counts for food sold in takeaways, restaurants and canteens will be tried within six months in the latest move to tackle Britain's obesity crisis, the government's Food Standards Agency announced today.

It is seeking volunteer companies to pioneer listings of energy content on wallcharts and menus and believes the rest of the industry will follow suit once a standardised simple guide is agreed under the scheme, which will not be backed by legislation.

Men in Britain now get a quarter of their food energy intake outside the home. The figure for women is 21%. A number of chains already offer nutritional information on websites or leaflets but now the catering industry will be expected to go much further.

Officials at the agency hinted that if the calorie counting is a success, the drive for information will be expected to go further with a possible extension of the traffic light scheme that applies to food sold in supermarkets and other stores. This involves red labels where levels of salt, sugar or fats are too high, yellow for medium levels and green for low.

Pizza Hut became the first company to say it was interested in becoming one of the pilot companies. In New York firms with more than 15 branches across the US must carry the calorie count in the same size print as the name of the food. They face fines for breaking the law and preliminary results suggest consumers are already cutting their intake from such food by nearly 100 calories a meal. Guidelines in Britain suggest women need 2,000 calories a day, men 2,500 and children between five and 10 1,800.

Tim Smith , chief executive of the food agency, said: "We're used to seeing nutrition information when we are shopping and there is no compelling reason why we shouldn't have more consistent information in order to make decisions … when we go out." But he made clear there would be no "calorie police" to enforce the scheme.