On this page
What are the causes of overweight and obesity?
The standard classification of BMI recommended by the World Health Organization for adults is based on the association between BMI and illness and mortality, and is as follows:
- Underweight: BMI <18.5
- healthy weight: BMI >18.5 and BMI < 25
- overweight but not obese: BMI > 25 and BMI < 30
- obese BMI > 30.
There are various factors in childhood that can lead to increased risk of obesity in later life. These include lack of breastfeeding, poor intrauterine nutrition, low birth weight, timing of maturity and poor diet and low levels of physical activity.
Why is obesity a National Health Priority Area?
Our obesity rates are among the highest in the world, with around 1 in 4 Australian adults being obese. Obesity can cause a range of health problems, and adds to Australia's health costs significantly. (Australia's health 2010 pages: 29-31, June 2010)
Data from the 2007-08 national health survey showed the figures for the general population aged 20-50 years; 21% were obese and 35% were overweight. And more males were overweight or obese (64%) than females (49%). (Australia's health 2010 pages: 276-277, June 2010)
Based on measured height and weight in 2007-08, 25% of children aged 5-17 years were overweight or obese. ( Australia's health 2010: in brief pages: 22-23, June 2010)
In April 2008, the Australian Health Ministers' Conference (AHMC) [external link] agreed to make obesity a health priority area. AHMC hoped that it would:
- Help drive collaborative efforts aimed at tackling obesity at national state, territory, and local levels
- Ensure that obesity receives the attention it deserves as a matter of urgency
What are the risks of overweight and obesity?
People who are overweight, or in particular obese, have higher rates of mortality and morbidity than those who have a healthy body weight (WHO 2000). Being overweight increases the risk of illness overall and from specific conditions. Obesity increases the risk of coronary heart disease, Type 2 diabetes, gall bladder disease, ischemic stroke, osteoporosis, sleep apnoea and some cancers. Weight loss can reduce the severity of some of these conditions, as well as improving cholesterol levels, blood pressure and glycaemic control and decreasing the symptoms of osteoarthritis (WHO 2000).
Trends
The marked and steady increase in bodyweight over the past few decades is one of the strongest and best-known trends in Australia's health. Our obesity level puts us squarely among the 'worst' third of OECD countries. ( Australia's health 2010: in brief pages: 22-23, June 2010)
The rise in overweight and obesity has occurred among Australian males and females of virtually all ages. Many experts are concerned about the effect this may have on our rates of diabetes, heart disease and other disorders, perhaps even on our life expectancy. ( Australia's health 2010: in brief pages: 22-23, June 2010)