By Katherine Sellgren
BBC News, education and family
Legislation introduced in 2008 means school meals must be balanced
More primary school children in England are choosing vegetables in the school canteen - but large amounts are being consigned to the bin.
A survey by the School Food Trust of 6,700 children at 136 primary schools in 2009 found 57% took vegetables, but 41% of these foods were not consumed.
Just 23% of children took fruit, but this was an improvement on 16% opting for it in the trust's 2005 survey.
Children were choosing fewer starchy foods cooked in fat, the study found.
The researchers found 40.7% of vegetables were wasted and 32.6% of salad was left uneaten. A similar proportion of fruit (32.7%) was left uneaten.
"This suggests that more needs to be done to encourage pupils to finish eating the vegetables, salad and fruit which have been taken," the report said.
Carbohydrate and vegetable dishes, such as vegetarian lasagne, also had a high wastage rate of 34.6% and this after a low take-up rate of 5.4%.
In total, 24% of pupils' food and drink was not consumed, the study found, compared with 23% in 2005.
Less than half the schools (48%) were meeting the required standard for iron content, only 54% made the grade for zinc content and just 19% were meeting the standard for sodium content.
"More work needs to be done," the report said.
Just 12% of schools provided a portion of fruit per pupil every day and about a third provided less than half a portion, the research found.
"Clearly, more still needs to be done to help caterers provide especially more fruit, and to encourage pupils to eat more fruit."
Trained field workers recorded pupils' food choices and consumption
The survey found over half the pupils (51.3%) were drinking water with their lunch in 2009, up from 30% in 2005. But 26% of this water was wasted.
The research was conducted between February and April last year by trained field workers who recorded the food and drink items taken and eaten by 10 randomly selected pupils.
When pupils had finished their lunch, the field workers weighed and recorded any leftovers.
The research was carried out six months after schools in England were required by law to meet new food and nutrient standards, to ensure children ate more healthily.
In 2008-09, 39% of pupils in primary and special schools in England opted for school dinners.
'Pat on the back'
The School Food Trust's chief executive, Judy Hargadon, said the trust was delighted by the progress being made.
"Caterers across the country deserve an enormous pat on the back for the huge shift in what's being offered to children, and for all they've done to encourage pupils to give healthier options a try.
"The figures certainly show that there's still a lot of work to do, both in fully meeting the standards across the board and in encouraging children to eat what's on their plate."
Schools Minister Diana Johnson, said: "We want to make sure children are eating a healthy, nutritious lunch at school because we know this helps their concentration and behaviour in the classroom.
"Making sure children get a portion of fruit and vegetables each day and the right amounts of fat, salt and sugar, is a vital step towards reversing childhood obesity and protecting their health.
"School cooks, lunchtime supervisors and caterers should be congratulated for the efforts and keep up the good work."