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Obesity: weighty matters
The world is getting weightier and the trends suggest that it will continue. Why is obesity such a problem - and what can be done about it?
Obesity is more than just a disease. It is also about more than just eating too much. As the American Obesity Association says, "No human condition – not race, religion, gender, ethnicity or disease state – compares to obesity in prevalence and prejudice, mortality and morbidity, sickness and stigma."
Trends in obesity
The American Obesity Association has identified some general and regional trends in obesity, among them:
* In many developing countries, obesity co-exists with under-nutrition – a body mass index of less than 18.5 (see panel below).
* In economically advanced regions of developing countries, prevalence rates of obesity may be as high as in industrialised countries.
* Globally, women generally have higher rates of obesity than men do, although men may have higher rates of overweight.
* Prevalence of obesity in children and adolescents is on the rise in both developed and developing regions.
* Obesity is relatively uncommon in African and Asian developing countries, although when present, it is more prevalent in urban than in rural populations.
* In the region of the Americas, obesity rates for both men and women are increasing in both developed and developing countries as well as countries in transition.
* Many south-east Asian countries are undergoing a ‘nutrition transition’ involving a shift in the structure of diet, decreased physical activity and rapid increases in the prevalence of obesity.
* Some countries in the eastern Mediterranean region report high obesity prevalence in adults, particularly women. The prevalence rates for women in this region are generally higher than for women in most industrialised countries.
* The prevalence of obesity has increased by about 10 per cent to 40 per cent in the majority of European countries over 10 years.
* The prevalence of obesity in the Western Pacific region is highest in the urban areas of the Pacific islands such as Samoa. Although obesity prevalence is low in China, in areas where obesity does exist it is most common among women and in urban areas.
The weight epidemic
Obesity – and being overweight – is an epidemic. There are more than one billion overweight adults in the world, at least 300 million of whom are clinically obese.
In the US, over 65 per cent of adults are obese or overweight (see panel for the clinical definition of the two terms). In the UK, 22 per cent of the population is estimated to be obese and 75 per cent overweight. There is no doubt that it is an increasing health problem that is showing no signs of going away.
Latest studies on obesity
The latest study from the Centers for Disease Control and Prevention (CDC) estimates that about 112,000 deaths are associated with obesity each year in the US.
Obesity is responsible for 9,000 premature deaths each year in the UK, where the Department of Health estimates that current trends suggest that one in three adults and a fifth of all children – a total of 13 million people – will be obese by 2010.
The costs of obesity
Obesity and being overweight affect more than the individual - they also affect healthcare costs around the world. In the US, direct healthcare costs attributable to obesity are estimated to have been $52 billion in 1995, rising to $75 billion in 2003.
Disease risks of being overweight
Obese and overweight people are at increased risks from developing chronic diseases, including type 2 diabetes and cardiovascular disease.
The likelihood of developing type 2 diabetes rises sharply in obese people. About 85 per cent of people with diabetes have type 2 diabetes and of these, 90 per cent are obese or overweight. This is also a problem for the developing world, with increases in type 2 diabetes seen in India and the Middle East, as well as in China, Latin America and the Caribbean.
The good news is that studies show that even a modest cut in weight in people who are obese or overweight improves their chances of better health.
Causes of obesity
One of the main causes for a rise in obesity is the change in our diets over the past few decades as well as a decline in physical activity. Food portion sizes have increased, sugary drinks are more common and people, on average, are less active. In fact, more people are likely to be found watching TV than walking or taking part in sports activities.
Tackling the obesity problem
Obesity is not an easy problem to tackle because it involves changing people’s lifestyles and encouraging them to eat more healthily, control the size of food portions and take more exercise.
There is a renewed focus for promoting healthier lifestyles in the UK where good eating habits are being taught to children in school in an effort to ensure health benefits later in life.
Better labeling and restrictions on advertising food to children have also been called for. In fact, the Public Health Committee of the British Medical Association has already called for a ban on 'junk food' advertising to children.
In the US, the CDC is also expanding its activities in schools aimed at promoting physical activity and good nutrition.
There are more than one billion overweight adults in the world . 
Obesity is a global phenomenon
The World Health Organization (WHO) says that current obesity levels range from below five per cent in China, Japan and some African countries to over 75 per cent in Samoa. Yet even in relatively low prevalence countries like China, rates are almost 20 per cent in some cities.
An estimated 22 million children under the age of five are said to be overweight worldwide. The US Surgeon General says the number of overweight children in the US has doubled and the number of overweight adolescents has trebled since 1980.
The prevalence of obese children aged 6-11 years has more than doubled since the 1960s, according to WHO. Obesity prevalence in American youths aged 12-17 increased from five per cent to 13 per cent in boys and from five per cent to nine per cent in girls between 1966-70 and 1988-91.
The statistics are significant. Behind them, of course, are quality of life factors such as stigma and prejudice that add a different dimension to the epidemic of this 'modern disease', obesity and being overweight.
Obese or overweight?
Body mass index (BMI) is a measure of body fat based on height and weight that applies to both adult men and women. It is an indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.
In metric measurement, BMI is a person's weight in kilograms divided by the square of their height in metres (kg/m2). A BMI over 25 is overweight and a BMI of over 30 is obese.
* Under 20 is underweight
* 20-25 is normal
* 25-30 is overweight
* Over 30 is obese
The World Health Organization reports that mean adult BMI levels of 22-23 are found in Africa and Asia, while levels of 25-27 are prevalent across North America, Europe, and in some Latin American, North African and Pacific Island countries. BMI increases among middle-aged and elderly people, who are at the greatest risk of health complications.
BMI is the accepted measure, although WHO says some confusion about the consequences of obesity arise because researchers have used different BMI cut-offs.
Sources
American Obesity Association
Centers for Disease Control and Prevention
UK Department of Health
World Health Organization
