In the 80ies, dieting was all the rage – in the developed world. While joggers clogged the streets and fitness centres boomed in western cities, ethnic groups in various regions of the developing world have been taking to less movement – and more junk food. A disparity which the Association for the Advancement of Science warns has lead to a "global epidemic of fat" spreading from the rich industrialised countries to threaten the health of the developing world.

Microwaves and Remote controls

Overweight is defined as an excess amount of body weight including bones, muscles and fat. But obesity generally refers to an excess amount of fat, very often the result of overeating and too little exercise.

Obesity is said to go back to the early days of modernisation half a century ago. Since then the amount of caloric intake has increased sharply while physical activity has decreased – due to the introduction of electronic household gadgets, cars and other forms of effort-saving equipment.

An effect which is now threatening the health of developing countries.

Australian Aborigines, for example, have been reported to develop a very high prevalence of obesity and diabetes after changing their traditional "hunter-gatherer" lifestyle – high physical activity and low-calorie, low-fat, high-fibre diet – to a Western lifestyle.

On Ratonga, capital island of the Cook Islands, the proportion of adult men who were obese increased from 14 per cent in 1966 to 52 per cent in 1996 - the highest levels of obesity were found with those with non-manual jobs.

According to the WHO, the fundamental causes of the obesity epidemic are sedentary lifestyles and high-fat, energy-dense diets, reflecting the profound changes in society and the behavioural patterns of communities – despite the fact that obesity can result from a genetic or biological predisposition.

Pushing up health-care costs

Indeed, overweight and obesity are now so common in both the developed and the developing world, that according to the WHO, "they are now replacing the more traditional public health concerns such as undernutrition and infectious diseases as some of the most significant contributors to health".

Just when western countries are attempting to reduce health-care bills, its eating habits appear to be pushing costs higher. In the western world this dilemma is causing furrowed brows – and experts are questioning just how this could happen, even after the 80s health movement.

The opinions vary: Media experts blame TV advertising, saying ads show girls telling viewers to eat, eat, eat – but who are as thin as a rake themselves. And TV ads - especially for children’s foods - generally praise sweet candies and sugary desserts and not healty greens such as broccoli, beans and brussel sprouts.

Nutritionists say that despite all the fuss about diets, people still exercised too little.

Others say it all has to do with a lucrative diet industry fighting an even more aggressive food industry and of an exercise industry competing against a high-tech industry of labour-saving devices.

And it is also about pitting a fast, frenetic workday pace against the inevitable temptation to stretch out on the sofa at the end of the day.

The psychology of diet

But looking at the reasons why people eat too much, a closer look at the psychological side of the story is inevitable. "We eat out of emotional needs. We eat when we’re happy, we eat when we’re sad. We’ve grown up in a way that food is a substitute for many other things," Dr. Lawrence Cheskin, director of the John Hopkins Weight Management Center stated in a US newspaper shortly. When times are tough – recession and unemployment part of everyday life – food very often substitutes loneliness, isolation and alienation.

Jane Fonda-like fitness freaks of the 80s generally belonged to single areas in the US, such as New York and Los Angeles – very often the more well-to-do parts of these cities. Women, children and the elderly living in ghettos and poor city districts were and still are prevented from going out alone for exercise and leisure activities by high crime levels.

Various studies have shown that minorities have poorer nutritional diets and are less physically active. According to the Center for Disease Control and Prevention, 27 per cent of blacks and 21 per cent of Hispanics of all ages are considered obese, around 30 per cent overweight, compared with around 17 per cent whites.

The obesity epidemic

An epidemic which is now spreading to the Third World? According to the American Obesity Association, "in economically advanced regions of developing countries, prevalence rates of obesity may be as high as in industrialized countries".

The WHO has concluded that global epidemic projections for the next decade are so serious that public health action is urgently required. So far, however, Third World Countries are still linked to malnutrition in the minds of the public rather than obesity and overweight. But as the medical burden of obesity may threaten to overwhelm health services all over the world, obesity has already become a principal, and global public health problem.