Body Mass Index


Lt Col Reynolds
Since the most common measurement for obesity is the body mass index, or BMI, let’s learn more about it. Dr. Patel, would you explain how BMI is measured and how it’s used?

Dr. Patel
Absolutely, Dr. Reynolds. BMI refers to a person’s weight in kilograms divided by height in meters squared. Many BMI calculators automatically translate the calculation into pounds and inches for easy reference. BMI measurement is an inexpensive and easy-to-perform method of screening for weight categories, which include underweight, normal weight, overweight, and obese.

When calculating BMI, however, it’s also important to keep in mind that:

  • Women tend to have more body fat than men
  • Older people tend to have more body fat than younger adults, and
  • Highly trained athletes may have a high BMI because of increased muscle mass rather than increased body fat.

In general, however, if a patient’s BMI is below 18.5, this means that they are underweight. If they are between 18.5 and 24.9, this indicates that they are at a healthy weight. If their BMI is between 25.0 and 29.9, they are categorized as overweight. And, if their BMI is 30.0 or above, this suggests that the patient is obese.

For most adults, BMI is considered the definitive diagnostic tool for obesity. Further assessment tools used by providers may include skinfold thickness measurement, as well as measuring the waist, hip, and neck circumferences.