Food portion weights in primary and secondary school lunches in England.

Background: National Nutritional Standards for school lunches were reintroduced in 2001, and included guidance on portion sizes for primary schools. For the first time since 1997, nationally representative data on school food portion sizes in England have been collected using direct assessment rather than reported portion sizes.

Methods: Food portions were weighed directly in foods served in nationally representative samples of primary and secondary school meals.