It was Coco Chanel who once said that you can never be too thin or too rich, but she was undoubtedly wrong on at least the first count! The belief that the thinner an individual is, the better, is in fact a dangerous misconception, because research has shown that just as mortality rises along with weight, it also rises with excessive decrease in weight. It is therefore essential to prevent unnecessary weight loss and to be realistic about one's optimal weight for height.
In our society with its ideals of unrealistic thinness, the problem of underweight is often not taken seriously, yet it can cause as much distress as its opposite. The basic cause of underweight is an inadequate energy intake and/or excessive burning up of energy. People who suffer from it are generally very active, tense or nervous get very little rest, smoke, or eat poorly and irregularly. It can of course also affect those whose food intake is low and energy expenditure high due to illness, fever, gastro-intestinal disturbances, cancer or hormonal imbalances.
In recent years, however, there has been an alarming increase in an entirely different cause of excessive thinness, namely self-induced starvation and purging (laxative abuse, vomiting). Otherwise known as anorexia nervosa and bulimia, these serious eating disorders are confined almost exclusively to adolescent girls and young women.
Many researchers maintain that the incidence of eating disorders has increased significantly over the past two decades. Anorexia nervosa used to be a relatively rare condition, but is now said to occur at a rate of one new case per year for every 100-200 middle- and upper-class adolescent and young adult women (between 0,5 and 4% of the population). The incidence of bulimia is estimated to be somewhat higher (5-19%). Anorexia nervosa occurs throughout adolescence and young adulthood with peaks in early adolescence (12-13 year olds) and at about 18 years old. Bulimia sometimes appears as a complication of anorexia nervosa (also called bulimia nervosa) in middle adolescence, or as an isolated phenomenon during adolescence or young adulthood.
Anorexia nervosa
The American Psychiatric Association has defined the following criteria for the diagnosis of anorexia nervosa:
- Refusal to maintain a body weight which is above a minimal normal weight for age and height - for example, weight loss or failure to gain; weight during a period of growth, resulting in a maintained body weight which is 15% below normal.
- Intense fear of gaining weight or becoming fat, even though underweight.
- Disturbances in the way in which one's body weight, size or shape is perceived; for example, the person claims to feel fat even when emaciated or believes that one area of the body is too fat even when obviously underweight.
- In females, absence of at least three consecutive menstural cycles when there is no other underlying cause.
Bulimia nervosa
Criteria for the diagnosis of bulimia have been defined as:
- Recurrent episodes of binge-eating (rapid consumption of a large amount of food in a short period of time).
- A feeling of lack of control over eating behaviour during the eating binges.
- Regular self-induced vomiting, use of laxatives or diuretics, strict dieting or fasting, or vigorous exercise, in order to prevent weight gain.
- A minimum average of two bingeing episodes a week over a period of at least three months.
- Persistent over-concern with body shape.
