"Increasing numbers are coming in with extreme diets. When a child is growing ... the body needs glucose and carbohydrates for energy."
The negative side-effects of the obesity battle are not purely physical. Last November, Girlguiding UK published a report based on interviews with 80 Brownies aged seven to 10. Each was shown cartoon images of different-sized girls. Almost all the Brownies made a connection between being slim and being happy, popular and academically successful. Overweight girls would be miserable, unsuccessful and likely to be bullied.
Cecilia, from Kent, is 11, 5ft 2in and weighs 9 stone. She eats a balanced diet and has dancing lessons three hours a week. She also worries constantly about her weight.
"She definitely feels she's obese," her mother said. "And she feels people are making moral judgements about her: that she's the way she is because she's lazy. It's wrong that we should openly discuss children's weight in this way. It's state-sponsored bullying."
All pupils are now weighed in the final year of primary school. But Cecilia's mother refused to sign the consent form. "It's public humiliation," she said. "It's an appalling world kids now live in."
Ms Freeman believes that schools should not divide foods into good and bad: chocolate desserts can be an entirely valid part of school dinners. She suggests serving a dessert that includes both chocolate and fruit. "It would give children energy through the afternoon," she said.
Ms Ringwood believes chocolate, biscuits and sweets should not be given purely as treats. "If it's a treat, children feel they're only entitled to them if they've been good. Then if you help yourself to a biscuit you feel guilty. It can lead to secret eating," she said. She recommends that schools teach children to grow and prepare food, giving practical lessons in how to balance a diet.
Ms Freeman runs lessons in preparing balanced meals at her local primary. "There's a lot of confusion around food," she said. "People need guidelines to understand a balance is needed. If you boost the variety of what children eat, that can be vital to a healthy attitude to food."
British Dietetic Association: www.bda.uk.com.