When body matter matters

By Smriti Daniel

From billboards to television shows, from the catwalks to the fashion magazines, it has always been apparent that being "good looking" in our times, is sometimes as simple as just being slim. However, being underweight is not always a choice, and can sometimes be a symptom of an underlying disease, says Dr. Senaka Rajapakse, Consultant Physician, and Senior Lecturer in Medicine, at the Faculty of Medicine, Colombo.

This week, he speaks to Mediscene about what exactly it means to be underweight and the impact your weight has on your wellbeing.

• Being underweight - when is it normal and when is it a health problem?

There are two issues with regard to low body weight. One is the individual who has always been underweight, from childhood.

Such a person maybe completely normal. Recent weight loss, of more than 4.5kg over the past six months, could be due to serious disease, and needs further investigation.

Loss of weight ultimately results in underweight. Some diseases cause weight loss with increased appetite, while others cause weight loss with reduced appetite. In all these conditions, weight loss occurs involuntarily, meaning that the patient does not make an effort to lose weight.

Causes of weight loss with increased appetite can include diabetes mellitus, over-activity of the thyroid gland, problems in the gut which result in reduced absorption of food and increased physical activity, such as starting on exercise training.

Causes of weight loss with reduced appetite are also varied and can include cancer, HIV infection and AIDS, under activity of the adrenal gland, chronic diseases of the lung and depression. Smoking can also reduce your appetite.

• How do you calculate your correct weight?

To get an idea of what your ideal body weight is, you need to calculate your Body Mass Index or BMI. The BMI is calculated by the following formula. BMI = body weight (in kg) divided by height (in metres) squared i.e., BMI = body weight (kg) height (m) 2.

Based on the recommendations of the National Institute of Health (NIH) and World Health Organization (WHO), which are accepted by most expert groups, the normal BMI is between 18.5 and 24kg/m2. If your BMI is below 18.5, you are underweight.

The table on this page can be used to find out where you lie on the BMI scale. If you don't fit in, i.e., if your BMI is below 19, you are most likely underweight.

• What about voluntary weight loss?

In some situations, weight loss is voluntary. Influenced by information that to be thin is good, healthy, and makes you better looking, many people, young people especially make an effort to lose weight. This is done by reducing food intake, and by exercising. As long as the person is within normal body weight this does not cause any problems.

Some individuals, however, take voluntary weight loss to extremes. This can result in the condition known as Anorexia Nervosa. Anorexia nervosa is commoner in young women, although it can be found in older women and men. A patient with anorexia nervosa will often have the following features:

• The body weight is maintained below 15% of ideal body weight.

• The patient has a fear of weight gain.

• The patient is obsessed with body image - being thin is all that is important, and any sacrifice is made to maintain thinness. Although the patient may already be extremely thin, she continues to believe that she is not thin enough

• Absent menstrual periods. Anorexia nervosa is a disease. It can have dangerous effects, including osteoporosis (fragile bones), growth delay, heart failure or cardiac impairment, psychological disturbances and difficulty in learning, nausea or bloating, irregular or absent menstrual periods and infertility. Karen Carpenter, of the brother and sister singing duo 'The Carpenters' died of anorexia nervosa.

How seriously does it impact overall health?

As discussed earlier, if the patient does not have an underlying disease which is causing weight loss, and if he or she does not have anorexia nervosa, being underweight does not by itself cause major problems. There is an increased chance of osteoporosis among underweight patients. Women who are underweight can also have problems during pregnancy and childbirth.

Do children who are born underweight continue to be so into adulthood?

Children who are born underweight are quite different from adults who are underweight. Being underweight at birth is not usually associated with being underweight in adult life. Babies can be underweight at birth either because they are born before term, or because they have had growth retardation while in the mother's womb.

What makes it so difficult for some people to gain weight?

Patients with weight loss due to illness will find it difficult to gain weight. In some of these conditions the body spends more energy than it obtains by food. For example in an overactive thyroid gland, or in cancer, the body utilises energy at a faster rate. In diabetes, the body loses glucose with the urine. Also in some of these conditions, especially cancer, long standing disease, heart failure etc, the poor appetite results in the body not getting enough calories.

How do doctors approach the treatment of such underweight patients?

If weight loss is present, the doctor must look for one of the causes listed above. Often it is difficult to diagnose anorexia nervosa, because the patient often denies that she has an eating problem. However, the doctor should suspect the condition if the patient is very thin, and she seems to be relatively unconcerned about it.

Detailed history regarding eating habits will help in diagnosing the condition. The patient will often be reluctant to admit that there is a problem, and her perception of her own body image will be abnormal, in the sense that she will think that she is too fat, even though she is very thin.

Can the ill effects be reversed?

It can be reversed if diagnosed early. Nutrition must be given, usually in a supervised setting. The patient has to be monitored carefully. Psychological support by counsellors, psychologists and the family will be essential. A psychological method known as cognitive behavioural therapy is used. There are no definite drugs for the condition, although drugs to reduce anxiety may be of some use. Suddenly increasing the nutritional intake can also be dangerous, and re-feeding has to be done carefully.

Some people may try steroids and other medicines in an attempt to bulk up - is this a good idea? If not, what can you do for yourself?

If you are just thin, and do not have an eating problem or any other illness, as long as your weight is within normal range, you do not have to do anything about it.

Disregard what others say; being within normal weight is healthy, and will help you live longer. If you are underweight, seek help from a doctor who will evaluate you and determine if there is anything wrong. He may do some blood tests to exclude certain conditions. Take a balanced diet, with more calories. Meet a dietician and get yourself a balanced diet chart.

Do not use any kind of drugs to improve your weight. If you do not have any disease, all you need to do is to take regular exercise and eat more. Never take steroids - they have lots of side effects - they make the bones thin, make you more likely to get infections, can cause diabetes and high blood pressure, and make you look ugly. There are certain drugs which stimulate the appetite, but these are generally not recommended, and are full of side effects. Vitamins are thought to help to stimulate the appetite by many people, but their effect is probably imagined rather than real.