The following information is for education purposes only. If you fall in the high or low BMI or WC range, please contact your physician to discuss your concerns. The medical provider is the right person to advise you on the next steps. Awareness is the key to the healthy body. 

Body mass index (BMI) is an approximate measure of your best weight for health. It is calculated by dividing your weight in kilograms by your height in meters squared (m2).

BMI is intended for adults only, as children and adolescents are constantly growing. This makes it difficult to have set values for BMI cut-offs for young people. However, in adults who have stopped growing, an increase in BMI is usually caused by an increase in body fat. You can calculate your BMI using the CDC Adult BMI calculator here.

Your BMI will classify you as ‘underweight’, ‘healthy weight’, ‘overweight’ or ‘obese’, as defined by the World Health Organization. If your BMI is:

  • under 18.5kg/m2 – you are considered underweight and possibly malnourished
  • 18.5 to 24.9kg/m2 – you are within a healthy weight range for young and middle-aged adults
  • 25.0 to 29.9kg/m2 – you are considered overweight
  • over 30kg/m2 – you are considered obese.

Risks of being overweight (high BMI) and physically inactive

If you are overweight (with a BMI over 25kg/m2) 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 18.5kg/m2), you may be malnourished and develop:

  • compromised immune function
  • respiratory disease
  • digestive diseases
  • cancer
  • osteoporosis.

Imp: BMI calculations will overestimate the amount of body fat for:

  • body builders
  • some high-performance athletes
  • pregnant women.

IMP: BMI calculations will underestimate the amount of body fat for:

  • the elderly
  • 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 anorexia nervosa
  • extreme obesity.

Waist circumference is a better indicator of increased disease risk

Waist circumference can be used to indicate health risk for chronic diseases.

For men:

  • 94 cm or more – increased risk
  • 102 cm or more – substantially increased risk.

For women:

  • 80 cm or more – increased risk
  • 88 cm or more – substantially increased risk.

Although the tendency to deposit fat around the middle is influenced by a person’s genes, you can still take this genetic tendency into account and do something about it.

Being physically active, avoiding smoking, and eating unsaturated fat instead of saturated fat have been shown to decrease the risk of developing abdominal obesity.

Source: Better Health