What is BMI?

So if you are not new to dieting and exercise then you would have heard the term BMI thrown around quite a bit. BMI stands for Body Mass Index and it is a way of calculating your total body fat to see whether you are in a normal, under weight or over weight range.

measuring waist

The reason it is important to know your BMI reading is that it will help you determine a healthy weight range to aim for if you are not already in it. Being within your healthy weight range is not only about looking good, but also about your quality of life and long term health. 

The way BMI is calculated is by dividing your weight in kilograms by your height in meters squared. There are numerous online calculators, which make this process very easy. 

As there are a number of factors that can influence your BMI the figures are considered to be an estimation only. The factors that can cause inaccuracies in BMI are:

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
  • 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 or people with extreme obesity. 

How to Read your BMI:

  • Under 18 – you are very underweight and possibly malnourished.
  • Under 20 – you are underweight and could afford to gain a little weight.
  • 20 to 25 – you have a healthy weight range for young and middle-aged adults.
  • 26 to 30 – you are overweight.
  • Over 30 – you are obese.

Risks of being overweight and physically inactive
If you are overweight (BMI over 25) and physically inactive, you may develop:

  • Cardiovascular (heart and blood circulation) disease
  • Gall bladder disease
  • High blood pressure (hypertension)
  • Diabetes
  • Osteoarthritis
  • Certain types of cancer, such as colon and breast cancer.

Risks of being underweight
If you are underweight (BMI less than 20), you may be malnourished and develop:

  • Compromised immune function
  • Respiratory disease
  • Digestive disease
  • Cancer
  • Osteoporosis
  • Increased risk of falls and fractures.

So the fact is that keeping your BMI in the normal range will benefit you not only in appearance, but health wise as well. If your BMI is above the normal range and you would like to start making some healthier lifestyle choices read my article on dieting 101 to get you started!

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