Written by Professor Arne Astrup
What is obesity?
Obesity is a heavy accumulation of fat in the body’s fat cells to such a serious degree that it rapidly increases the risk of obesity-associated diseases and mortality. The fat may be equally distributed on the body, on the stomach (apple-shaped) or on the hips and thighs (pear-shaped).
An excellent method to measure obesity and overweight is the Body Mass Index (BMI). It is calculated as your weight (in kg) divided by your height (in metres) squared. People of average weight are considered to have a BMI between 18.5 and 25 (kg/m2), and people with a BMI of 25 to 30 (kg/m2) are considered overweight, while people with a BMI of over 30 (kg/m2) are considered obese. Test your BMI here.
How common is obesity?
Obesity is found a little more among men than women. Stomach obesity is more frequent and occurs in 30 per cent of adult men and, to a lesser degree, in adult women. Obesity and stomach obesity are rapidly increasing, especially in young people. The occurrence of obesity has increased by five fold since the Second World War.
Most importantly, being overweight and obese may cause several psychological problems like a feeling of inferiority, often caused by discrimination. Furthermore, many physical problems are related to obesity, like difficulties in breathing, personal hygiene, pain in the knees and back and skin problems.
People suffering from obesity more frequently have high blood pressure and diseases related to hardening of the arteries, with blood clots in the heart and the brain.
Other related problems include non-insulin dependent diabetes,gallstones, some types of cancer, difficulties in mobility and increased risk of mortality.
What causes obesity?
Obesity can be hereditary, hence some people are at increased risk. However, obesity only develops from overeating, irregular meals and lack of daily physical activity. Many people think that when a disease is hereditary, it is inevitable that you will suffer from the condition but this is not true.
If the people in Europe had grown up in China with plenty of non-fat foods and hard daily work in the rice fields, only a few of them would be overweight or fat. It is lifestyle which determines how the genes develop. The fact that the existence of obesity has increased by five times since the Second World War, is hardly due to a change of our genes. On the contrary, our lifestyles have changed rapidly.
Besides genes, food and physical activity, it is possible that other so far unknown elements may play a part.
When is obesity dangerous?
With a BMI of more than 25, it is advisable to change lifestyles and lose weight, especially if it is stomach obesity (apple-shaped). The waist circumference may be used in order to determine if you are apple-shaped.
Men with a waist circumference of more than 94cm (37in) and women with a waist of more than 80cm (31.5in) should not further increase their weight. An increased risk of obesity-related diseases is present with a waist circumference of more than 102cm (40in) for men and more than 88cm (34.6in) for women.
If your BMI is more than 30, it is required that you lose weight.
How is obesity treated?
A weight loss of 5 or 10kg among obese patients has a very positive effect on the risk of heart and blood-vessel diseases. The weight loss will not only reduce blood pressure and blood-cholesterol, but also have a beneficial impact on obesity-related diseases.
The help of a dietitian can result in weight-loss of 5 to 10kg in more than 90 per cent of patients put on regular diets of, for instance, 1500 to 2000 kilo calories per day, based on calorie-counting. Another option to attain the same result involves changing to an unlimited consumption of low-fat foods.
After losing weight, thorough guidance on shopping and preparation of foods with a fat-energy-percentage of 20 to 25 per cent is of paramount importance, in order to stop the weight being put back on.
Furthermore, it is important to increase daily physical activity. Patients, who do not reach a satisfactory weight-loss on a diet, may be subjected to medical or surgical treatment.
When is medical treatment necessary?
Obviously, not everybody needs medical treatment. If an obese patient loses weight by diet and exercise, there is no need for such treatment. Furthermore, many people do not want to have medical treatment
The main problem is to limit the treatment to persons who actually need it such as:
- those with a BMI of more than 30kg/m2 who have not reduced weight by diet changes, exercise or lifestyle changes.
- those with BMI of more than 28kg/m2 and the presence of risk elements or complications.
- those with BMI of more than 28kg/m2 who have experienced a previous rapid increase of weight.
Medication for obesity is not yet recommended for children as we have no knowledge of possible negative effects on puberty and later eating behavior.
How to maintain your weight after weight loss?
Weight loss is obtained most effectively by diets provided by professionals. However, by far the greater challenge is achieving a way of life that maintains the weight and reduces the chances of putting it back on.
Obesity is a disease that you cannot expect to be cured of or be under clinical control within a few weeks or months. Thus, short-term treatment with medicines should be rare.
Medical treatment must be expected to be necessary for years, possibly your whole life, in order to maintain the weight-loss and reduce illness. However, there is a lack of experience in medical treatment of obese patients for more than two years.
The information concerning efficiency and safety of medicines used in combination with other medicines is very limited.
Until we obtain more knowledge, medical treatment should be reserved for patients with high risk of complications, or patients who already have complications, for whom it is very important to maintain their weight.
Which medicines may be used for medical treatment?
Medications for obesity treatment contribute to weight loss and increase the number of patients who achieve a weight loss of more than 5 or 10 kg. After the weight loss has been completed, the medicine helps prevent the patient from regaining the weight.
Medicines that reduce appetite help the patient eat less and stick to their diet. They work even without dieting but the loss is larger when there is a combination of the two. This is possibly due to an increased feeling of fullness and the reduction in hunger pangs because of the medication.
Some appetite-reducing medications increase the burning of calories, which intensifies the appetite reducing effect.
Another type of medication reduces the fat absorption from the bowels. It is only active in the bowels and, therefore, doesn’t have the typical side effects frequently seen for appetite-reducing medications. For efficient diets, where patients with a BMI above 35kg/m2 achieve a weight loss of about 15 kg within a period of six months, appetite reducing medications and other medicines to treat obesity may contribute to an extra weight loss of 3 to 6kg.
Medication should only be used in a treatment program including diet, exercise and lifestyle changes.