12. What is BMI/BMR?

BMI, or Body Mass Index, is a simple math equation of weight (kilograms) divided by height (meters). The World Health Organization categorizes BMI as:

  • Normal: 18-25
  • Overweight: 25-30
  • Obese I: 30-35
  • Obese II: 35-40
  • Obese III: 40 and above

There are drawbacks to using BMI as a measure of health, however. It does not take into account fat mass versus lean mass. For example, consider: Body weight=fat free mass + fat mass

Fat mass is a more useful tool for predicting health and maintaining a healthy body fat percentage is important. This can be measured using a body composition analyzer, like the Seca scale in our office.

BMI also does not take into distribution of body fat. An android, or apple, shape has more fat deposited around the waist. This is less healthy than the so called “pear-shape”. Body measurements help to evaluate where fat is deposited. Ethnic differences also exist for BMI.

Know your numbers! During weight loss, it is important to see the number on the scale moving in the right direction. But it is more important to see improvements in body fat percentage or in laboratory results.