The World Health Organisation has defined how the Body Mass Index (BMI) is calculated. BMI (kg/m 2) = weight (kg) present [height (meters) x height (meters)]. The BMI for a healthy body is between 18.5 and 23.9. If your BMI is between 24 and 27.9 you are overweight. A BMI of greater than 28 is considered to be obesity. It is important to note that the BMI calculation does not apply to growing children, the elderly who are unable to accurately measure their height, to athletes and muscle builders and to pregnant women. Obesity can also be diagnosed by measuring your waistline. A male with waist measurement of 85 cm or more is overweight and if the measurement is 95 cm or more he is obese. A female with a waist measurement of 80 cm or more is overweight and if the measurement is 90 cm or more, she is obese. Waist size reflects the visceral fat content, so waist circumference is also a good way to measure obesity. It can be combined with body mass index as a second method.