Overweight and obesity refers to excess body weight. People who are overweight or obese have higher rates of death and illness than people of healthy weight, particularly from cardiovascular disease, type 2 diabetes, some musculoskeletal conditions and some cancers.

The main factors influencing overweight and obesity are poor diet and inadequate physical activity. Increased energy intake from the diet without an increase in energy expenditure through physical activity will result in energy storage as fat and weight gain.

Rates of overweight and obesity are continuing to rise in Australia. Collecting information on these trends is important for managing the associated health problems. The AIHW regularly reports on overweight and obesity as a risk factor for chronic disease. Better data are needed to monitor trends in overweight and obesity among particular groups over time, especially children.

Overweight and obesity can be measured in a number of ways, including the commonly used body mass index (BMI). BMI is an internationally recognised measure of overweight and obesity at a population level for both adults and children (Cole et al. 2000; WHO 2000). For more information and to calculate your BMI see Overweight and obesity an interactive insight.


Cole TJ, Bellizzi MC, Flegal KM & Dietz WH 2000. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ 320:1240–3.

WHO (World Health Organization) 2000. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. Geneva: WHO.