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How Is Obesity Defined?

Body Mass Index (BMI) is a measure calculated from a person’s weight and height. It provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems. BMI is calculated by dividing your weight in kilograms by your height in meters squared. That number should be between 18.5 and 24.9. The National Institutes of Health has defined certain classifications of weight based upon the BMI:

Classification

BMI Range

Underweight

Less than 18.5

Normal

18.5 – 24.9

Overweight

25.0 – 29.9

Obese

30.0 – 39.9

Extreme Obesity

Greater than 39.9

According to a report released on July 7, 2011 by the Trust for America’s Health and the Robert Wood Johnson Foundation, two-thirds of all adults and about a third of all children and teenagers in the United States are overweight or obese.  In fact 16 states have obesity rates over 30%.  Colorado has the lowest rate at 19.8%.  Twenty years ago no state’s obesity rate exceeded 15%.  Indeed we have an epidemic!

You should discuss with your physician whether your goal should be to attain a normal BMI. For people with a lot of muscle mass, such as trained athletes, a healthy BMI may actually be somewhat higher than what the table would indicate. For most people, however, these categories are a useful guide.

Another body measurement that is related to health risk is the waist circumference. It seems that the location of fat makes a difference as far as health risk. Fat in the waist carries a greater health risk than fat in hips or thighs. Scientific studies have shown that people whose waists exceed the targets in the table below have a higher risk of health problems.

Gender

Healthy Waist Circumference

Men

Less than or equal to 40

Women

Less than or equal to 35

In my next post I’ll talk about the health risks from being overweight.

For Your Health – Dr. Bob