Supporters say the tests, which will measure the children's Body Mass Index (BMI), will help to increase parental awareness of obesity, while opponents claim the initiative could lead to overweight children being misinformed about the state of their health and, even worse, being bullied.

The Loughborough researchers “ Dr Emma Rich, Professor John Evans and Rachel Allwood, from the School of Sport and Exercise Sciences “ agree that the potentially damaging effect on the children themselves could outweigh the benefits.

They have also expressed concerns over the use of BMI as a measuring tool, as research evidence suggests it to be very imprecise, and not a method that should be used on its own or casually to make judgements about a person's health'.

The team's opinions stem from their research into the experiences at school of girls and young women suffering from eating disorders, such as anorexia nervosa and bulimia. Their findings revealed that many sufferers strongly believe that their illness was nurtured or exacerbated, or sometimes even caused, albeit inadvertently, by the well-meaning actions of teachers and health experts in schools.

"Our research indicated that schools are increasingly pressing children to monitor their own diets, body shapes and levels of physical activity, which can unintentionally cause children to become anxious about their appearance, their weight and the food they're eating, when they have no need to be," says Dr Rich.

Some of the young women interviewed as part of the team's study recalled traumatic experiences of being weighed in schools, which led to them becoming increasingly unhappy with their bodies. One girl commented: "I used to be overweight, and I remember one time at school when the whole class got weighed. The teacher said, Oh, it's the big one' and I was the heaviest in the year."

Dr Rich continues: "The pressures on children to monitor their bodies are relentless, and they're not just confined to school in PE and health lessons, they occur everywhere “ in playgrounds, at lunchtimes, in corridors, on TV and web sites, and in the home.

"It's therefore unsurprising that recent surveys have shown that many young people who believe they are overweight or obese definitely are not."

Based on their own and others' research evidence, the Loughborough team believe that a degree of panic that has been generated about the issue of obesity, and child obesity in particular, which is often ill-founded. Children are increasingly considered to be an at risk' group. As a result, governments around the world are investing a great deal of money in a range of new school-based health imperatives that focus on getting young people to exercise more, change their diets and lose weight.

"The initiatives being proposed to tackle the issue are driven by an assumed connection between claims of escalating rates of obesity and particular lifestyle practices, such as a decline in physical activity, poor diet and too much time spent at a computer or watching TV. Many of these claims are patently false. It's now acknowledged by some researchers that the relationships between weight, diet, physical activity and health are far more complex and uncertain than is currently being suggested," comments Dr Rich.

"While there may be health risks for individuals at the extreme ends of the weight continuum, for example those who are extremely thin or morbidly obese, there's a great deal we don't know about the relationship between weight, health and physical activity. Some studies suggest that people who are overweight' according to their BMI but are physically active, may well be healthier than their thinner counterparts who are not physically active. In other words, size, shape and weight might not be the issue at all."

As well as the BMI measurements being introduced in the UK, other practices now in operation elsewhere include lunchbox inspections and health report cards, and it has been reported that in Australia schools have fat laps', where children considered to be overweight are required to run around the school field during lunch breaks.

The Loughborough researchers say it is difficult to see how such degrading practices can be considered as positive. "Such initiatives would be considered unethical and unjust in other social contexts. They could have a hugely negative impact on young people.

"If translated into policy and practice in schools, this latest measure will certain damage the health of some children," they warn.

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