Body mass index (BMI) is one method used to estimate your total amount of body fat. It is calculated by dividing your weight in kilograms by your height in metres squared
(m ).
Differences in BMI between people of the same age and sex are usually due to body fat. However, there are exceptions to this rule, which means a BMI figure may not be accurate.
•BMI calculations will overestimate the amount of body fat for:
body builders some high-performance athletes pregnant women.
•BMI calculations will underestimate the amount of body fat for the elderly, and for people with a physical disability, who are unable to walk and may have muscle wasting.
•BMI is also not an accurate indicator for people with eating disorders like anorexi nervosa or people with extreme obesity.
•BMI is not considered the best measurement
of weight and health risk. A person’s waist circumference is thought to be a better predictor of health risk than BMI.
BMI Range:
>Under 18.5 – you are considered underweight and possibly malnourished.
>18.5 to 24.9 – you are within a healthy weight range for young and middle-aged adults.
>25.0 to 29.9 – you are considered
overweight.
>Over 30 – you are considered obese.
Risks of being
overweight (high BMI)
and physically inactive
If you are overweight (with a BMI over 25)
and physically inactive, you may develop:
•cardiovascular (heart and blood
circulation) disease
•gallbladder disease
•high blood pressure (hypertension)
•type 2 diabetes
•osteoarthritis
•certain types of cancer, such as colon and breast cancer
•depression and other mental health
disorders.
Risks of being
underweight (low BMI)
If you are underweight (BMI less than 18.5), you may be malnourished and develop:
•compromised immune function
•respiratory disease
•digestive diseases
•cancer
•osteoporosis.