Weight gain and obesity develops when the energy supplied from the food and drink you consume is greater than the energy your body needs for physical activity and other metabolic processes. Obesity is a disease involving abnormal or excessive body fat accumulation that can cause impaired health.

The World Health Organisation estimates that more than one billion people world-wide are overweight, 400 million of whom are obese (World Health Organisation, Obesity and Overweight, 2006).

Australia is part of this growing epidemic. Around seven million Australian adults are overweight or obese – 52% of women and 67% of men (Australia’s Health, Australian Government, Department of Health and Ageing, 2008).

Am I Morbidly Obese?

There are several medically accepted criteria for defining morbid obesity. You are likely to be morbidly obese if you:

• are more than 45.4 kg over your ideal body weight, or
• have a Body Mass Index BMI of over 40, or
• have a Body Mass Index BMI of over 35 and are experiencing severe negative health effects such as high blood pressure related to being severely overweight

How Is Obesity Measured?

Answering this question may give you the courage you need to take the first step and help you to determine if you are possibly morbidly obese and a potential candidate for weight loss surgery.

Obesity is measured by the body mass index (BMI). The BMI reflects a person’s weight in comparison to their height. The BMI is calculated by dividing your weight in kilograms by your height squared in metres (weight [kg] ÷ height2 [m2]). For instance, a woman who is 1.67m in height and weighs 65kg would have a BMI of 23.3, which is considered to be within the healthy weight range. A BMI of 30+ is considered obese.

Generally speaking a BMI between 20 and 25 is considered healthy weight, but be aware that BMI does not take into consideration body frame size or muscle mass. Note that these are approximate values, and are intended to be used only as a rough guide.

BMI Classification

18.50 and below         Underweight
18.50 – 24.99             Normal range
25.00 – 29.99             Overweight
30.00 – 34.99             Obese class 1
35.00 – 39.99             Obese class 2
40.00 +                      Obese class 3