Lena Zavaroni's early death was so tragic, and is yet another reminder that we should always take eating disorders very seriously.

Uncontrolled anorexia nervosa is a malignant disease, with a higher death rate than most cancers, yet it can be cured if the person, usually a young woman, can only be persuaded to eat.

That is easier said than done. It has to be repeated time and again that anorexia isn't the 'slimmer's disease' that we so often hear it called in the media.

It goes far deeper than that.

It is about a young woman not wanting to grow up. It's much more about someone wanting to stay a child than wanting to keep fashionably slim. And it usually starts around puberty. In many anorexics the signs are there long before they become fashion conscious.

It's difficult to know for sure what causes girls to become anorexic in the first place, but most cases seem to arise out of pressures on them, perhaps from family, perhaps at school, perhaps from friends or classmates. There may be an inherited tendency to react to stress by not eating - but that hasn't been proved.

Whatever causes it, the signs are clear. The girl stops eating, and goes to great lengths to hide the fact that she isn't eating normally. She may seem to be eating her meals, but actually be hiding the food away somewhere. She may say she dislikes people watching her eat, so she tells her family she wants to eat in her room.

As she starts to lose weight, she chooses baggy clothes to wear - to hide her shape. So a thick sweater to hide the fact that she is losing her curves, slacks that don't show her stick-like legs (anorexics hardly ever wear skirts), and a bouncy hair-do to offset her sharp face are all warning signs to parents and friends. They also make me doubt the current theory that anorexics see themselves as too fat - because if they did think that, they would choose clothes that make them look thinner, not fatter.

Their big loss of weight occurs just at the time when their friends of the same age are usually going through their biggest weight gain. In normal puberty there is a 'growth spurt' as the hormones kick in and girls take their womanly shape. Pounds are put on the chest and hips as the breasts and pelvis develop. Inches in height may be put on in a year. So becoming much thinner around this time is not normal.

At this early stage, too, girls with anorexia often take up exercise to excess. They say that this is their way of keeping fit, but this, too, for them is really just another way to lose weight. And they hide the fact that they are not eating by saying that it's the exercise that is keeping them slim. So be suspicious if a young woman friend or relative exercises every day. No one should do that - not even professional athletes. They take two days off a week to let their muscles recover and re-stock up on their fuel. Anyone exercising seriously for athletics, sports or dancing should take professional advice on how much they should do - and good professionals will tell you how to rest, and how to eat, as well as how to improve performance.

Excess exercise drives the weight down further, and has another crucial effect on the developing young woman - it stops their periods. Most girls start to have periods when they get to 47.5 kilograms in weight - about 7 stones 7. Drive your weight below this, and your periods stop.

As the weight falls further, the real toll on health begins. Once all the fat storage cells are empty, the starving body starts to live on more essential fat cells - such as the fat in the nervous system (including the brain). Any appetite that once existed fails, and there isn't the energy now to continue with the exercise. The muscles waste, too, so that the girl becomes weaker. And the most important muscle of all, the heart, begins to lose mass, so that it can't beat strongly enough to maintain the circulation.

When the girl gets to this stage, it's very difficult to know how to get the weight back on, because any excess load on the heart - and that can even mean a meal - may stop it. So by the time the girl is under five and a half stones experts are needed to guide her through and help her back to health.

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.