KEY POINTS:
She might be the slim girl in the gym who exercises hard-out then goes for a run every other day, in between netball and touch rugby and training for triathlons.
She might be the overweight mother who began dieting after her children were born. Or the professional woman in her 40s who has been yo-yo dieting since her teens and has gone on endless weight-loss programmes.
These women have a secret. When no one is home they take to the fridge, emptying it in an eating spree which is out of their control. They might pick up a super-size takeaway on the way home and stop again to buy a few bags of lollies. They will eat the lot.
The women are not strictly bulimic and neither are they anorexic. Unlike bulimics, not all will purge their food by making themselves throw up or by taking laxatives, although some do. Unlike anorexics, they are not out to starve themselves. But they are universally unhappy about what they are doing, and over time are damaging their health.
Binge-Eating Disorder is more common than might be thought, say researchers at Otago University's department of psychological medicine, who are conducting a study of 200 New Zealand women who have the condition.
The main method of treatment is cognitive behaviour therapy, which aims to change dysfunctional thinking about food, body shape and weight. Yet fewer than half who are treated this way fully recover, and others relapse. The Otago study aims to find out why, and to test how the therapy can be more effective.
There is no typical pattern as to who binge-eats, says clinical psychologist Dr Virginia McIntosh. They are usually, but not always, women and they come in all shapes, sizes and ages.
Some plan their binges when they know they will have the opportunity to eat without check. Others intend to have just one biscuit but go on eating. It might be a short burst or go on for several hours.
For some it's a reaction to restricting their eating - banning foods they see as bad - because they are trying to lose weight. Then they give in to an overwhelming urge.
The binges can occur more than twice a week, while some people binge every day or more.
And they really pig out? "Yeah, they do," says McIntosh. "And people can eat really, really big quantities and they feel out of control and they don't like it.
"Some people will eat two litres of ice cream and half a loaf of bread, half a pizza, really big quantities. Often they'll start off eating normal food but it will just escalate, they just can't stop it.
"We've got underweight people who are restricting [what they eat] who will have binges and they may be doing other things to try to compensate. They may be over-exercising, they may be purging after bingeing.
"There are people of absolutely normal weight and then there are people who are really heavy, who are overweight, who may still do some of those compensatory things or they may not."
A pattern of binge-eating over a prolonged period can bring a sense of hopelessness. They think, "I can't do anything about it" and give up trying to diet or exercise.
Depression is a problem but not always - "they may be okay about other things but feel hopeless about where they have got to with binge-eating."
People seek help because they feel out of control. Food is dominating their lives.
When not bingeing they are thinking about food and when bingeing they are feeling bad about doing it.
It is distressing, and, mostly, it's under wraps. There are women who have had problems for 20 years who have never told anyone.
The study is focusing only on women for comparative reasons but an unknown number of men are also binge-eating. For both sexes, some occupations are more hazardous than others, says McIntosh, and she's not talking about working in a chocolate factory.
"Among men, working as a jockey. Some sporting activities like gymnastic training, ballet dancing, occupations where body shape and size is an important part."
Worrying about weight and shape flows on to trying to lose weight. This means trying to eat less. But this leads to being hungry, under-nourished and feeling deprived.
When a cue or trigger is sparked, such as a stressful day or an argument, people are poised to binge. The foods they go for are not healthy: "It's rare for people to binge on broccoli."
And partly to blame are the mixed messages society sends about weight and body shape.
Images are everywhere of women who are too thin. The commercialisation of food has grown and people are encouraged to eat more. Advertisers dangle temptation with fast and high-sugar food and offer incentives - super-size meals, big combos and 50c more to upsize a meal.
On one page of a woman's magazine are gorgeous, glossy photographs of tasty, appealing food but on the next page are the dieting tips.
"One of the things we really work hard on in the therapy programme is to help people to enjoy food and we all like tasty food, we're built that way ... helping people to be able to enjoy food without it being something that rules their lives and they feel terrible about."
In Auckland, Dr Maree Burns co-ordinates Eden [Eating Difficulties Education Network], a community agency which sees people who have identified an eating problem.
Society's focus is on telling people to be careful about what they eat, about dieting and regulating food intake, she says. But this is counter-productive because dieting and restraint can be why people develop binge-eating problems.
The agency sees people with two main types of binge-eating. One is where people haven't eaten for hours because they are trying to be "good" but are so hungry they lose control.
Others are trying to deal with intense emotions - problems of anxiety, unhappiness or sadness. With both types, society strongly encourages dieting, yet food is advertised as a panacea.
Burns believes you cannot divorce people's eating behaviour from the environment in which it is taking place. She also warns about confusing and mixed messages. Having control of your own body and appetite is prioritised in Western culture, but television shows make fun of fat people and many of the current glut of weight-loss programmes have an unsavoury edge, she says.
"They do show people who have bigger bodies or who eat in ways that aren't supposedly controlled and there are a whole lot of experts telling them what they have to do. There's often quite a voyeuristic kind of element that goes on with showing people in that way and with the weighing and the wobbling of body parts. I feel quite uncomfortable with those kind of shows."
Eden works on a model of trying to encourage people to develop an intuitive eating style, which is much more about learning to discern when you are hungry and full, rather than eating to external cues.
The Otago researchers say there is a public health impact of binge-eating because it is associated with obesity, a growing health problem in New Zealand and other Western countries.
About 3 per cent of all women are likely to have bulimia at some time in their lives and another 5 to 10 per cent will embark on some form of binge-eating, says McIntosh - "it's a sizeable problem".
