Australia's Obesity Epidemic

What is Obesity?

Obesity is a condition where excess body weight accumulates to the extent it may have an adverse effect on health, leading to a reduced life expectancy.

This occurs when an individual’s energy intake exceeds their energy expenditure - the larger the imbalance the more rapid the weight gain.

Obesity is a health risk and can lead to a range of medical conditions and
complications.

• In Australia, more than 17 million Australians are overweight or obese.
• More than 4 million Australians are obese (BMI > 30.0 kg/m2).
• If weight gain continues at current levels, by 2020, 80% of all Australian adults and a third of all children will be overweight or obese.
• Obesity has overtaken smoking as the leading cause of premature death and illness in Australia.
• Obesity has become the single biggest threat to public health in Australia.
• On the basis of present trends we can predict that by the time they reach the age of 20 our kids will have a shorter life expectancy than earlier generations simply because of obesity.
• Aboriginal and Torres Strait Islander Australians are 1.9 times as likely as non-indigenous Australians to be obese.

How much are the effects of obesity costing Australia?

• $37.7 billion: the estimated direct and indirect costs of obesity and obesity-related llnesses in 2008/09.
• $6.4 billion a year: the estimated cost of loss in productivity due to obesity through absenteeism, presenteeism and premature death.
• 7,200: the estimated number of Australians that  die each year due to obesity and obesity related illness.
  
• Research shows that obesity intervention policies aimed at
  reducing the prevalence of obesity in Australia will yield strong
  benefits for the economy.

Causes of Obesity

A range of factors can cause obesity. Factors in childhood and adolescence are particularly influential, since a high proportion of obese children and adolescents grow up to be obese adults.

Factors known to increase the risk of obesity include:

• Genes – researchers have found that genetics play a part in regulating body weight. However these genes explain only a small part of the variation in body weight.
• Birth factors – some studies suggest that a person is more likely to become obese later in life if they experienced poor nutrition in utero, had a low birth weight and weren’t breast fed. However, other studies show that high birth weight is a stronger risk for becoming overweight.
• Eating more kilojoules than you use – whatever your genetic background, you will deposit fat on your body if you eat more energy (kilojoules) than you use.
• Inactivity – for most of us, physical activity is no longer a natural part of our daily schedule. Obese people tend to live sedentary lifestyles.
• Modern living – most modern conveniences, such as cars, computers and home appliances, reduce the need to be physically active.
• Socioeconomic factors – people with lower levels of education and lower incomes are more likely to be overweight or obese. This may be because they have less opportunity to eat healthy foods and take part in physical activities.

The Obesity Epidemic: One of the major reasons for most of us to make the decision to lose weight is the significant health gains that can be made. Australians as a whole are becoming more and more overweight every year.

Current WHO (World Health Organisation) statistics estimate that in Australia this year:

75.7 % of males over 15 yrs have a BMI 25+ (overweight)
66.5 % of females over 15 yrs have a BMI 25+ (overweight)
28.4 % of males over 15 yrs have a BMI 30+ (obese)
29.1 % of females over 15 yrs have a BMI 30+ (obese)

Some of the diseases associated with obesity

Am I obese - BMI versus Waist Measurement?

How to Measure your Body Mass Index (BMI): There are no perfect measures of overweight and obesity. Body Mass Index (BMI), which is calculated by dividing weight in kilograms by height in metres squared, is used most often – particularly in assessing overweight and obesity at the population level.

At the individual level however, BMI does have some limitations in that it can be influenced by age, gender and ethnicity. Also, BMI does not distinguish fat mass from lean mass, nor does it necessarily reflect body-fat distribution.

For example, a woman 1.67m in height and weighing 65kg would have a BMI of 23.3, which falls within the healthy weight range. However, this may not be not an accurate predictor of the proportion of body fat to lean mass or fat distribution, particularly in older people or muscular individuals such as athletes, because of the differences in proportions of fat mass to lean mass and distribution of body fat.

The BMI cut-off points are based on associations between chronic disease and mortality and have been adopted for use internationally by the World Health Organisation (WHO).

BMI Ranges:

• Underweight: <18.50
• Normal range (Healthy Weight): 18.50 - 24.99
• Overweight: >25.00
• Pre-obese: 25.00 - 29.99
• Obese class 1: 30.00 - 34.99
• Obese class 2: 35.00 - 39.99
• Obese class 3: >40.00

Waist circumference: A person’s waist circumference may be a better predictor of health risk than BMI. Having fat around the abdominal organs and enlarged waist circumference, regardless of your BMI, means you are more likely to develop certain obesity-related health conditions. Fat predominantly deposited around the hips and buttocks does not appear to have the same risk. Men and post menopausal women are at greater risk of excess fat in the waist region.

Waist circumference for women: a waist circumference of 80cm or over indicates increased risk of obesity related health conditions. A waist circumference of 88cm or more indicates a substantially increased risk.

Waist circumference for men: a waist circumference of 94cm or over indicates increased risk of obesity related health conditions. A waist circumference of 102cm or more indicates a substantially increased risk.