Fighting The Obese Enemy
The Age
Wednesday February 13, 2002
In some cultures, corpulence is a sign of prosperity and status. In southern Nigeria, for example, young women pay to become obese by attending "fattening rooms", despite evidence linking such weight gain to diabetes.
In Australia, supermarket shelves groan with "lite" and fat-reduced foods; magazines promote the latest celebrity diet; sports programs celebrate sun-bronzed, super-fit Aussies; stick-insect supermodels are rewarded handsomely for their gauntness; men (and women) work out obsessively in gyms; young women starve themselves into anorexia or bulimia; businessmen jog around city blocks to work off corporate lunches; masochists swim endless laps in suburban pools.
Never before in our history has there been such a consciousness of the need to eat well and exercise regularly; never before have we had such levels of overweight and obesity, particularly in our children.
Given our almost obsessive preoccupation with body image and weight, why is it that Australia now has one of the highest rates of obesity in the world?
Obesity is a global epidemic affecting both developed and developing countries. In 1998, there were more that 250 million obese people worldwide, equivalent to 7 per cent of the adult population.
Reflecting this trend has been a significant increase in the proportion of overweight and obese Australians. In 1999, for example, 65 per cent of men and 45 per cent of women aged 25-64 were reportedly overweight, compared with 52 per cent of men and 35 per cent of women 10 years earlier. Experts predict that by the year 2025, as many as 30-40 per cent of the Australian adult population could be obese (as distinct from overweight).
The trends in children's obesity are similarly alarming, with 20-25 per cent of primary school children now considered overweight or obese.
Studies indicate that overweight and obesity in Australia are more common in lower socio-economic groups, rural populations, some immigrant groups and indigenous people, suggesting a complex set of economic, cultural and environmental factors.
The effects of obesity have been well documented. Morbidity and mortality are higher among overweight and obese people than among lean people. Obesity significantly increases the risk of cardiovascular disease, type 2 diabetes, osteo-arthritis, gallstones and certain types of cancer.
An important feature of obesity is body fat distribution. Fat located in the abdominal region (central obesity) is associated with a greater risk of diabetes, coronary heart disease and high blood pressure. A disturbing trend is the number of Australian children with sedentary-related conditions usually associated with ageing. Adult-onset diabetes and other risk factors associated with heart disease are being found in children as young as seven.
Studies suggests that parents of overweight children are often not aware, or concerned, that their children are overweight. So prevalent is the problem that portly children no longer stand out from their peers as they might have done 10 or 15 years ago.
One of the most poignant psychological effects of obesity is poor self-esteem related to stigmatisation. Studies indicate that obese children may do less well academically, have poorer job prospects and be more socially isolated than their leaner peers. Obesity has been called the "last remaining socially acceptable form of prejudice" - unfair assumptions may be made about the capacity of obese people to cope with stress or heavy workloads and obese children can suffer terribly in the school yard.
The economic costs of obesity are also high. A 1992 estimate of the direct cost of obesity in Australia was $464 million. Direct costs relate to the prevention, diagnosis and treatment of illness. Indirect costs associated with lost productivity and premature death were estimated to be an additional $272 million. There are also intangible costs associated with diminished quality of life.
Only between 25-40 per cent of obesity can be attributed primarily to genetic factors. A child is more likely to be obese if his/her parents are obese, although this raises the question of whether cultural or biological factors are to blame. Metabolic rates also differ among individuals: the girths of some unfortunates seem to expand at the mere whiff of a pizza slice.
Previously it was thought that poor diet was the main cause of obesity; now the focus has shifted to declining levels of physical activity. Obesity is basically an imbalance between energy intake and energy expenditure. Fat not used for energy is stored in the body. This may have been a handy survival tool thousands of years ago, but storage of excess fat in today's sedentary world is potentially life-threatening. Metabolically, it has been suggested, we are still hunter-gatherers.
In the 1950s, a typical scene in suburbia might have been "home-maker" mum cooking meat and vegetables for the family. Eating was a shared ritual during which children also learned social manners. Today's families are more likely to eat high-fat fast food (ABS figures show that as a nation we spent more than $7.5 million on takeaway food in 1998-99) and to spend meal times watching television rather than socialising together and talking about the day's events. Changing social rituals and relentless exposure to advertisements for non-nutritious foods also affect attitudes to food consumption.
While a study of fast food in 1995-1997 found that Australians were choosing salads, yoghurt and focaccia instead of chips and hamburgers, the move towards healthier eating has not been accompanied by a reduction in obesity levels.
According to Dr Melissa Wake, of the Royal Children's Hospital, the decline in physical activity - whether organised sport, going for a bike ride or mowing the lawn - is "the single biggest factor" in the rise of obesity among primary-school children.
The news is not all bad. While participation rates for organised sport and recreational activity fluctuate, ABS figures show that "the number of participants has increased from 3.5 million in 1996-7 to 4.0 million in 1999-2000". Among the most popular activities are walking, swimming, aerobics and golf. Indigenous adults, people from low socio-economic groups, older people and people with disabilities are less likely to engage in exercise for sport, recreation or fitness.
However, a recently released University of South Australian study of trends in aerobic fitness in children between 1995 and 2000 found the aerobic fitness of Australian children to be declining at a rate of about 6 per cent a year. Compared to children of similar ages in 11 other countries, Australian children exhibited "poor to average aerobic fitness levels".
Environmental factors play a significant role in such trends. Our lives have been transformed by technology designed to reduce energy expenditure. Electric toothbrushes, remote control units, e-mail, ride-on mowers, elevators, computer games and videos have all reduced the level of physical activity in our daily lives.
Instead of kicking a footy or playing in a park after school, children and adolescents are more likely to "veg out" in front of the television set, play games on the computer or surf the Internet. It has been estimated that Australian children watch an average of three hours of television and spend 45 minutes on computers each day.
While studies have established a negative correlation between television viewing and obesity, a Royal Children's Hospital study of a group of primary school students found that television viewing contributed "only a small proportion of variance in child BMI (body mass index). Mothers' and fathers' BMI, children's food intake and exercise were more important predictors".
A recent study of how 11- to 13-year-old urban Australian children use their time highlights the need to take a different, targeted approach to the problem. Co-author Dr Tim Olds, from the University of South Australia, suggests that a family strategy of "screen-free days" could be implemented for the 8 per cent of boys identified in the study as spending a substantial amount of their time on television or video games. Girls whose participation in physical activity drops significantly at weekends could be encouraged to become involved in organised sport. According to Dr Olds, government-sponsored advertising campaigns "do little to change behaviour". Carefully focused strategies and a fundamental redesign of the built environment are needed.
The demise of the traditional quarter-acre block, with its potential for back yard cricket matches, and the trend to smaller back yards, have reduced the space available for children to play. The physical layout of suburbs means that children may need to cross busy roads to get to parks or playgrounds. Parental concern about safety may prevent younger children from walking or riding to school or playing outside. Instead of walking to the corner shop, adults are more likely to drive to a shopping complex.
Recently scientists in Melbourne announced a breakthrough "fat-burning pill", said to work best on "older patients battling a bulging stomach". While this will no doubt be highly lucrative, it is not the best way of tackling obesity.
The quick fix is precisely that, unlikely to lead to permanent or long-term change in daily habits. Drugs, surgical intervention and fad diets do not address the underlying causes of obesity: why do people eat so much? Why do they choose foods they know are nutritionally poor? What prevents individuals from being more physically active? Why are some groups more susceptible than others to obesity? Why aren't parents more responsible when it comes to monitoring children's food intake and physical activity?
In a recent diatribe against those who support a more interventionist approach to the problem of obesity, the economics editor for another Australian newspaper accused "anti-obesity" activists of undermining "liberal values" to do with freedom of choice and the "rights of individuals". Nothing was said, however, about the "right" of children to enjoy physical and psychological wellbeing under the guidance of responsible adults.
The World Health Authority recommends action at both the macro and micro levels. In addition to "universal strategies aimed at universal intervention", there needs to be "selective prevention of obesity" in at-risk sub-groups and individuals. Like the campaign against smoking, the battle of the bulge will not be won easily.
Michele Lonsdale is a writer and a former English teacher.
How do you measure up? Body mass index (BMI) is used to calculate body fat by dividing an individual's weight in kilograms by their height in metres squared (m2). Current BMI classifications for adults are: ? Underweight less than 18.50 ? Normal Range 18.50 - 25.00 ? Overweight 25.00 - 30.00 ? Obese 30.00 - 40.00 ? Morbidly obese more than 40.00 The suggested cut-off points for when a child is considered obese are: ? 2 years and over 20.09 for boys and 19.81 for girls ? 5 years 19.30 for boys and 19.17 for girls ? 10 years 24.00 for boys and 24.11 for girls ? 15 years 28.30 for boys and 29.11 for girls ? 18 years and over 30 for both males and females Cut-offs for overweight are approximately 5 points lower than that of obesity. Source: Better Health Channel www.betterhealth.vic.gov.au Other useful sites: National Health and Medical Research Council www.health.gov.au/nhmrc/ Australian Institute of Health and Welfare www.aihw.gov.au
© 2002 The Age