While around 60 per cent of these girls, aged 12 to 15, considered themselves to be overweight only 15 per cent could be medically classified under the category of overweight or obese.
The results of the annual School Health Education Survey have prompted the Schools Health Education Unit, to issue an appeal to end the 'obsession' with skeletal body shapes portrayed by the media and fashion industry.
According to David Regis, the unit's research manager, 'Youngsters worry about looking and being fashionable and there is a lot of evidence that girls get praise for being slim and pretty. The media is the most visible sign of this pressure but I don't doubt that some parents give children all sorts of messages about how they want them to look and about how they want to look themselves.'
He added, 'Girls are less likely to be comfortable within their skins if their mothers are unhappy with their own body shapes and always on diets.'
The Schools Health Education unit was initially started at the Exeter University and has nodw evolved into an independent survey and publishing company. The unit has collected details of health and behavior of over 700,000 pupils since 1977. They have also shown ink between the desire to lose weight and low self-esteem.
'They are the ones who are most likely to skip breakfast or lunch and eat a calorie-conscious diet but it is certain that most of these young women do not need to lose weight,' says the report. 'We would like to add our voice to those who wish to see a much greater variety of body shapes presented positively in print and other media.'
The survey revealed that 55 per cent of 12- to 13-year-old girls considered themselves as overweight with the figures rising to 56 per cent among the 14- and 15-year-olds. However on measuring the body mass index of these girls it was found that only 15 per cent of girls in the survey could be termed overweight of which four per cent were 'obese'.
Another four per cent could be classified as underweight and the remaining 81 per cent within the normal range.
Those who considered themselves to be overweight were also likely were most likely to skip breakfast with 36 per cent of them admitting to skipping lunch the previous day.
At the same time teenage boys appeared to be less concerned about their figures but had more cause for concern because the survey revealed that 21 per cent of males were above the desirable weight range. Most 14- and 15-year-old boys appeared to be overly concerned about tests and exams.
The proportion of older teenage girls worrying about their body image has not worsened significantly since the huge jump in the 1990s, said Mr Regis. 'The worrying thing is that the annual surveys show an upward trend among younger age groups,'he added.
Around 55 per cent of pupils said they had been 'picked on' or bullied and most felt it was due to their 'size or weight' or to the way they looked.