Body Mass Index

The Body Mass Index is an international standard which has been adopted to measure excess weight and obesity. The Body Mass Index (BMI), is defined as the weight divided by the square of the height and is expressed in kg/m ² (see box). The BMI estimates obesity and can be used to assess the health risks (co-morbidity) associated with it (see box).

BMI and obesity

A person is considered to be obese if their BMI is 30 kg/m² or greater. Alongside the BMI, body fat distribution should also be measured. It is now accepted that excess abdominal fat carries an increased risk to health. A waistline of more than 88 cm in women or 102 cm in men indicates visceral obesity and greater risk of developing other clinical problems.