The Food Standards Agency (FSA) is conducting an extensive survey of school meals in English secondary schools to establish whether or not they are meeting the nutritional guidelines laid down by the Government.
The survey, commissioned by the FSA and the Department for Education and Skills, comes at a time of growing concern that many teenagers are still eating too much sugar, fat and salt, leading to increased rates of obesity and diabetes.
There is also growing evidence that a poor diet affects academic performance.
Nutritional standards for school meals were laid down by the Government in April 2001. The standards dictate that a piece of fruit and one vegetable should be available to children every day, and that, on a day when one dish is cooked in fat, an alternative that's not cooked in fat should be offered.
Fish should be served at least twice, and red meat at least three times a week, the guidelines state.
It is the responsibility of the local education authority (LEA) - or, where the budget for school meals has been delegated to them, a school's governing body - to ensure that the standards are met.
Ultimately, the secretary of state may direct a school or LEA to meet the standards if it is failing to do so.
The meals survey will also question schools on the nature of their contracts with their caterers, the price they are charging for meals, the time children are given for eating them, and the availability of food from other sources.
The extensive survey will start in May, and findings are expected to be published in 2004.
Nutritional guidelines were introduced in schools following the results of a report published by the FSA in 2000. The National Diet and Nutrition Survey looked at the diets of children aged four to 18 and found that they were eating too much sugar, salt and saturated fat - and not enough fruit and vegetables.
It also found that while one-third of 15- to 18-year-old girls smoked, only 20% ate citrus fruit, and they drank two-thirds more fizzy drinks than milk.
Boys were found to eat, by weight, nearly four times as many biscuits as leafy, green vegetables.
Source: Caterer and Hotelkeeper magazine, 20-26 February 2003