Article: Anneke Kamfer from Ideas

The sight of obese adults and children has become common in most Western countries, and junk-food diets and low activity levels have been blamed. In the US, for example, 61 per cent of the population is either overweight or obese.

'Overweight and inactivity account for more than 300 000 premature deaths each year in the US, second only to tobaccorelated deaths,' reports the Journal of the American Medical Association. 'Obesity is an epidemic and should be taken as seriously as any infectious disease epidemic.'

Less well known is the fact that this epidemic has reached the shores of developing countries such as China, Brazil, Thailand and, yes, South Africa. As the populations of these countries become more urbanised, more calories are consumed because of the easy availability of high-fat, highcarbohydrate foods, coupled with a drop in physical activity.

In a city your day-to-day survival depends far less on physical exertion than in rural areas. Then there's the development of technology, which eliminates many labourintensive tasks and has us spending a lot of time in front of TV and computer screens. In fact, more than a third of the overweight adults in the world today live in developing countries.

No wonder the World Health Organisation (WHO) regards obesity as a global epidemic and formed an International Obesity Task Force to tackle it worldwide.

What is the situation in SA?
We are giving American fatties a good go: the Medical Research Council of South Africa has found that a staggering 55 per cent of adult women and 29 per cent of adult men are overweight in this country.

In addition, a quarter of our children between the ages of 12 and 18 can be classified as overweight or obese. In the past, under-nutrition was the focus of investigations into the nutritional status of South African children. But, says Dr Krisela Steyn, director of the MRC's newly formed Chronic Diseases of Lifestyle Unit, recent findings indicate that at least an equal number of children are being overfed.

As Westernisation changes the health profile of this country, we have the new global chronic lifestyle diseases to deal with. For example, four million South Africans have diabetes, six million of us suffer from high blood pressure and four million have high blood cholesterol levels. To top it all, we also have to cope with HIV/Aids and the poverty-related diseases of a developing country – bad news for our limited health resources.

Why is being big a problem?
Excess weight causes a host of health problems (see 'Weigh this up') and medical professionals are particularly concerned about the link between obesity and type 2 diabetes (also known as adult-onset diabetes).

Basically, people with this disease have eaten themselves sick: their blood glucose levels have become too high for the chemical insulin, produced by the pancreas, to do its job of transporting glucose to the cells, where it is used as energy.

Instead, the glucose is stored as fat. This sets off a vicious cycle, because the more body fat you have, the more insulin resistant you become and the more difficult it is for your body to burn fat and lose weight.

Dr Tessa van der Merwe, an endocrinologist and obesity expert at the University of the Witwatersrand, says that a diabetic probably finds it four times harder to lose weight than a non-diabetic.

In the US, the incidence of diabetes has tripled in the last 30 years. However, recent findings indicate that two-thirds of people suffering from type 2 diabetes live in the developing world. Dr van der Merwe says that it's particularly worrying that more and more South African teenagers are developing type 2 diabetes because of obesity, something that is more often found in people older than 45.

The long-term health prospects of these children are grim: diabetes is associated with an increased risk of stroke, diabetic retinopathy, which can cause blindness, and immune and kidney diseases. Even scarier is the fact that diabetics die of cardiovascular diseases at rates of two to four times higher than non-diabetics.

How can I tell if I'm obese?
Obesity is defined as being more than 30 per cent above ideal body weight. The body mass index (BMI) is used to measure for obesity in both sexes. It is not a perfect system – the measurements of a very muscular person may mistakenly place him in the overweight category – but it's a useful starting point. Your BMI is determined by dividing your weight in kilograms by your height in metres squared: BMI = kg/m². If you have a BMI between 25 and 30, you are classified as overweight. A person with a BMI of more than 30 is regarded as obese. Your waist measurement is another indicator: a waist circumference of more than 88cm in women What is to be done?
Don't rush out to have your jaw wired. The good news is that even moderate weight loss of as little as 10 per cent of your body weight can improve your health. A study found that people who lost 0,5kg over eight years reduced their risk of diabetes by between 37 and 62 per cent. Cutting only 50 kilojoules per day – that is a handful of chips – coupled with 45 minutes of walking five days a week will leave you with much brighter health prospects.

Weigh this up
Compared with people of normal weight, overweight people have up to four times the risk of diabetes, double the risk of high blood pressure, two to three times the risk of heart attack, double the risk of stroke, two to three times the risk of gallstones, double the risk of colon cancer and double the risk of osteoarthritis (a wearing away of the joints), especially in the knees. Excess weight also increases your risk of bowel, colon and breast cancer, reduces female fertility, and causes sleep disorders, bladder problems and psychological problems, such as depression and low self-esteem.