Girls as young as seven are worrying about their weight. In the last of a three-part series on women and body image, Women's Editor Christen Pears finds out it isn't just adults who long to be thin.

IT'S lunchtime at Framwellgate School, Durham, and I'm meeting a group of sixth formers to talk about body image. We sit down round a table and the girls tuck into an array sandwiches, crisps and bars of chocolate.

"Do you worry about how you look?" I ask. At first, they insist they don't, eating what they want and keeping exercise to a minimum, but it soon becomes obvious they do. After ten minutes I'm having the sort of conversation I would have with my 20 and 30-something friends, all about flab, squeezing into clothes that are too small, and feeling guilty when your resolutions for healthy eating crumble. They're all experts on their friends' figures. They know who's thin, who's fat, who's happy with their body and who isn't.

But these girls are just 16 and 17. They're all slim and yet all five feel pressure about their figures - partly from the media but mainly from their peers.

"You feel pressure when everyone else around you is like Twiggy," says Sammi Turnbull. "Being thin is kind of like an unspoken rule. Fat is associated with being unhealthy and unattractive."

The school Christmas ball is coming up, with its attendant awards ceremony. Categories include most fanciable female and the girls are convinced only those with good figures stand a chance of winning.

"They're going to vote for the slimmest, best-looking person and that's a bit of pressure," says Helen Bickford.

"We don't talk about how we have to be thin but people who aren't slim always talk about how they want to lose weight. It is important."

Holly Peacock has just started going to an aerobics class while Kirsty McKenzie is a member of a gym. Kirsty is particularly aware of her weight and body shape, a legacy of a childhood of gymnastics. When she was 14 or 15, she was told to go on a diet. It damaged her self-confidence and had serious repercussions.

'That sort of thing can make you go anorexic," she says. "I didn't eat for three days afterwards. When we were given sweets for doing good work at school, I would never have one. I deliberately didn't bring any money to school with me so I couldn't buy any food and then I'd go home and tell my parents I'd had a big lunch. Fortunately, I've got out of it now because I've got two brothers who pile food into them all the time."

The girls, who are all studying A-Level psychology, are well aware of the issues surrounding body image, and the factors that influence young women.

"The images you see in the media and in magazines are definitely a big factor for teenagers. It's not right that people should be trying to look that thin," says Heather Race.

Holly adds: "The thing that people don't realise is that you can't change your body shape, no matter how little you eat or how much exercise you do. Not everyone can be thin but everyone wants to be."

But while the group agrees that the emergence of curvier celebrity role models such as Jennifer Lopez and Beyonce are a welcome change, they can't help worrying about their own figures.

Holly lifts up her top to reveal the waistband of her size eight Top Shop jeans. She's sewn the button onto a piece of elastic so that she can fasten it. "There's no way I was going to buy a ten," she says jokingly, but then adds: "I've definitely more flab now I'm older but I'm not overly concerned. There's more to life than being skinny."

Obesity among children in Britain is on the increase. One in five 15-year-olds is now obese. Sedentary lifestyles and poor diet are to blame, putting children at risk of a host of health problems in later life, including heart disease, diabetes and cancer.

At the same time, thousands of youngsters are developing an obsession with losing weight. A survey conducted last year by Surrey University showed children as young as seven are conscious of their bodies and long to be thinner. Researchers found that half of girls aged between seven and 12 hanker after a slimmer shape.

Many are inspired by celebrities such as Geri Halliwell and Victoria Beckham, both of whom have admitted to suffering from eating disorders, while magazines aimed at teenage girls promote the message that thin girls are more successful and more popular.

Julie Seed, a clinical psychologist at Northumbria University, says eating disorders in the very young are becoming more common. The reasons behind the increase are complex, she says, but social pressure is one of them.

Underlying factors that influence a child's attitude to food include their parents' eating habits. If a child's mother is concerned about dieting, that can filter down to the child. As with adults, there are some children who are more likely to develop a disorder: children who are unhappy or who have had traumatic experiences such as the break-up of their parents' marriage. They don't have control over that aspect of their life but they can control their eating.

But there are other pressures. Julie says: "The fashion industry is also to blame. Children aren't encouraged to look like children any more beyond the age of eight. They want to dress like adults and look like adults and that's very much about being thin. They are coming more and more under the same pressure as adults. It doesn't mean they will develop an eating disorder but as they grow up, the chances are increased."

One alarming development is the growth of pro-anorexia sites on the Internet, where young women encourage each other in their eating disorders and share tips for losing weight. Dying to be Thin and Starving For Perfection are among more than 100 sites which promote eating disorders as a lifestyle. Most of the sites are thought to be run by American teenagers but they have spread to the UK. Experts are worried that they reinforce sufferers' belief that they are not ill and could lead to deaths, particularly among young girls who are insecure about their bodies.

While some children skip meals to shed weight, a growing number are turning to exercise to change their body shape. Youngsters as young as eight are attending gyms up and down the country. A survey carried out in September for The Sunday Times found nine out of ten gyms provided training and exercise programmes for children and teenagers. Some work out for six to eight hours a week in the quest for a better body.

Bannatyne's allows children under 16 to swim in the pool but they are banned from the gym, because at that age, their bones aren't fully formed and can be damaged by excessive exercise.

Corlette Boyle, manager of the Darlington club, says: "Children aren't doing as much physical activity as they were a few years ago so we would encourage them to exercise. It has physical, psychological and social benefits and gives them more self-confidence and self-esteem but you have to get the balance right.

"Children should know all about the benefits of healthy eating and exercise but it should be fun. It shouldn't become an obsession."

Sadly, it seems that as long as adults obsess about their bodies, children will too, and until we break free of our angst we will continue to foster a generation of youngsters wracked with guilt every time they visit the sweetshop.