Portion weights of food served in English schools: have they changed following the introduction of nutrient-based standards?

BACKGROUND: Mandatory food-based and nutrient-based standards for the food provided in English schools were introduced in 2008 (primary) and 2009 (secondary) and have had a positive impact on pupils' food choice and nutrient intake at school. There are no recommendations for portion sizes in England, although anecdotal evidence suggests that portions of food and drink sold in schools have decreased since the standards were introduced.
METHODS: Data were collected from 136 primary and 80 secondary schools in 2009 and 2010/11, respectively. All food and drink items provided at lunchtime were weighed on five consecutive days at each school. The mean and median weight, SD, and 25th and 75th centile for each individual food were calculated. Data were compared with the results obtained from similar surveys in 2004 and 2005, as well as with portion size recommendations for Scottish schools.
RESULTS: The proportion of food items that differed in weight since 2004/05 varied from 13% in primary schools to 29% in secondary schools. Changes in weight were equally likely to be positive or negative, with the exception of portions of fruit and vegetables, which had decreased. Primary schools were more likely to meet portion size recommendations than secondary schools.
CONCLUSIONS: Of the items that were directly comparable over time, a limited number showed a significant change in portion size since the standards for school food were introduced. Portion weight recommendations are based on a balanced healthy diet, and pupils should eat all the components of meals offered by schools to meet dietary recommendations.