06.Healthy body fat ranges
Body mass index
Body mass index (BMI) is often used by health professionals to assess whether a person is underweight, normal weight, overweight or obese. It’s your weight in kilograms divided by the square of your height in metres.
For example, if you weigh 65kg and are 1.65m tall, your BMI is 65 divided by 2.7225 (the square of 1.65), or 23.9. A BMI of less than 18.5 is considered underweight; 18.5 – 24.9 is normal; 25 – 29.9 is overweight; and 30 and over is obese. So in this case, a BMI of 23.9 would be considered healthy. The Results table indicates which scales give a BMI reading.
While BMI is a better indicator of health than weight alone, it’s far from perfect. It was originally developed as a statistical tool for analysing populations and not intended for individuals. The BMI categories don’t allow for very muscular individuals; a person with lots of lean muscle and low body fat will be heavy for their height and could be classed as overweight or obese. Similarly, some people may have a BMI that indicates they’re healthy when in fact they have too much body fat and little lean tissue.
You should only use BMI as a general guide to your state of health. Accurate analysis of your body fat percentage, measured over time, is more useful.
Healthy body fat ranges
Healthy body fat percentages vary considerably for from person to person. Factors such as age, sex and ethnicity all have an effect on what amount of body fat is right for an individual. The figures in this table can be used as a general guide. Very fit people, particularly elite athletes, may have lower body fat percentages than these.
Source: Gallagher et al, Am Clin Nutr. 2000; 72:694-701; based on NIH/WHO BMI Guidelines (healthy weight ranges) for whites.