According to the World Health Organisation (WHO), physical inactivity, smoking and an unhealthy diet are responsible for around 80% of deaths from cardiovascular disease, making it even more concerning that our biggest killer can be prevented.

Obesity alone has been established as a risk factor for coronary heart disease, stroke, Type 2 diabetes and some cancers.

With over 60% of Australians either overweight or obese*, a figure that has almost doubled over the last 20 years, what does it mean to be overweight or obese?

WHO defines overweight and obesity as ‘abnormal or excessive fat accumulation that may impair health'**.

Often a person's Body Mass Index (BMI) is used to determine if someone is within a healthy weight range. (BMI is calculated by dividing a person's weight (in kilograms) by the square of his height in meters (kg/m2)).

BMI is considered to be a good reflection of overall body fat, but it does not distinguish between fat and muscle. For instance, it may overestimate the fat in elite athletes, (such as rugby players or body builders), who have a large muscle build.

And, it may underestimate fat in older people who have perhaps lost muscle mass due to the aging process.

Waist circumference is a simple but good measure of abdominal fat and can be measured by placing a tape measure mid way between the top of the hip bone and end of the rib cage after exhaling.

The evidence suggests that the use of BMI in conjunction with measurement of waist circumference probably provides a more accurate assessment of someone's weight and risk profile.

* Australian Bureau of Statistics. National Health Survey 2007-2008.

** http://www.who.int/topics/obesity/en/index.html

Apples or pears?

People who gain extra weight around their waist are described as apple-shaped, while those who carry it around their hips and buttocks are termed pear-shaped. Those with the apple shape have an increased risk of heart disease, stroke, type 2 diabetes and some cancers. For every kilogram you lose, you can reduce your waist circumference by about 1 cm.