Draft Australian Dietary Guidelines (PDF, 3MB) - Eat For Health

How is healthy weight assessed?The most common approach is the use of the body mass index (BMI) calculated as weight (inkilograms)/height (in metres) 2 (kg/m 2 ).BMI is a measure of body size that is widely used as an index of relative risk of mortality andmorbidity at the population level [687, 691]. The association of mortality with BMI is a U-shapedcurve with the lowest risk within the healthy weight range [687, 706].An adult with a BMI < 18.5 kg/m 2 is categorized as underweight. An adult with a BMI from 18.5 to25.0 is a healthy weight, while an adult with a BMI ≥ 25.0 kg/m 2 is overweight and an adult with aBMI ≥ 30.0 kg/m 2 is obese [691, 707].However, this classification may not be suitable for all ethnic groups. Some groups may haveequivalent levels of risk at lower BMI (e.g. people of Asian origin) or higher BMI (e.g. people ofPolynesian origin) [708]. A BMI range of 23–28kg/m 2 may be desirable for people aged over 70[709]. BMI ranges have not been developed for Aboriginal and Torres Strait Islander people.Waist circumference is also used as a proxy for health risk in adults. A waist circumference above80 centimetres in women or above 94 centimetres in men signifies being overweight. A waistcircumference above 88 centimetres in women or above 102 centimetres in men signifies beingobese [13, 710].Growth during childhood means it is not possible to have a single set of numerical values for BMIcut-offs that apply to all ages and both sexes. Therefore, among children and adolescents, weightappropriateness is commonly categorised using Z-scores (or SD Scores) [711] or age-related cutoffvalues [712, 713]. For more information, see Appendix 3.4.1.2 Health effects associated with weight status4.1.2.1 AdultsOverweight and obesity are associated with increased risk of type 2 diabetes, cardiovasculardisease, some cancers, hypertension, musculoskeletal conditions, respiratory conditions, socialisolation, depression and other psychological disorders, sleep apnoea, cholecystitis, insulinresistance and metabolic syndrome, hernia, reproductive disorders, urinary incontinence and skinconditions [88, 89, 685]. About 70% of people who are obese have at least one established comorbidity,resulting in medical costs about 30% greater than their healthy-weight peers [714].DRAFT Australian Dietary Guidelines- December 2011 106