BMI is the standard measure used for clinical diagnosis of obesity.
It predicts health risks for most people accurately. It is not a reliable indicator for strength athletes and body builders (around 2% of the population) because it only takes height and weight into account – not body composition. Bodybuilders with very low levels of fat are often classified as ‘obese’ by this method.
BMI is a quick and easy gauging method. A BMI reading of 30 or more is classified as obese.
Below is a guide to BMI readings:
– < 18.5 = Underweight
– 5 – 25 = Normal
– 25-30 = Overweight
– > 30 = Obese
– > 40 = Morbidly obese
- divide your weight in kilograms (kg) by your height in metres (m)
- then divide the answer by your height again to get your BMI.
Body composition can be differentiated as:
Fat Mass (FM):
The proportion of total weight that is fat. This includes internal and external fat (adipose tissue).
Fat-free mass (FFM or lean mass):
The proportion of total weight that is not fat. This includes muscle, bone and internal organs.
The percentage of body fat is important information for assessing health.