By Martha A. Simpson, D.O., M.B.A.
Assistant Professor of Family Medicine
Ohio University College of Osteopathic Medicine

KNOWING YOUR BMI FIRST STEP TO REDUCING MANY HEALTH RISKS

Question: I went to the doctor for my annual physical. He said I was overweight. I weigh what I always have -- 150 pounds. He then told me not to worry about being overweight because I was a pear. Can you please tell me what he was talking about? I would also like to know how much I should weigh.

Answer: It seems that the problems of being overweight and obese are on the front page of the paper very frequently these days. Also, you may have noticed that what we consider to be overweight has changed in recent years.

Whatever the exact cutoff points between normal, overweight and obese are, it’s always a matter of judging what the appropriate weight is for a given height. For many years physicians used height and weight tables created by insurance companies. While these tables are good, more physicians are now using the Body Mass Index (BMI).

Obesity is defined as an excess of body fat tissue in relation to your lean body mass. So while we previously just looked at height and weight, we now understand that how much fat tissue you have, as well as how it is distributed is very important in predicting other health measures.

The Body mass Index (BMI) is a mathematical formula that is a weight to height ratio. It is more highly correlated with body fat content that any other height-weight indicator. A BMI of 22 to 25 is considered a healthy weight for almost anyone. A BMI under 18.5 is underweight. Mild obesity is a BMI of 25 that correlates to about 110 percent of ideal body weight. Severe obesity is a BMI of over 30 and morbid obesity is a BMI greater than 40. The BMI definition of obesity is the same for men and women. Your family doctor can supply you with a BMI table, or you can find a handy BMI calculator online at the Center for Disease Control and Prevention’s Web site. The specific URL is: http://www.cdc.gov/nccdphp/dnpa/bmi.

As for being a “pear,” the other important correlation between weight and disease is how the fat is distributed on your body. People with primary fat distribution around their abdomen are said to be “apple shaped” and are at increased risk for cardiovascular disease and insulin resistance. People who are larger around the hips are said to be “pear shaped.” A lying down waist measurement of over 35 inches in women and 40 inches in a man place these people at risk. Measuring the ratio of the waist to the hips also can help assess risk. If the waist is larger than the hip measurement, the risk is increased.

While this pear v. apple business is of some help, what you really need to know to properly “size up” your individual risk is your BMI. If you find that your BMI is above 25, I’d recommend that you take steps to reduce your weight so that BMI drops down into the normal range. This will reduce your risk of a host of diseases including Type II diabetes and heart disease.

Family Medicine® is a weekly column. To submit questions, write to Martha A. Simpson, D.O., M.B.A., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701, or via e-mail to readerquestions@familymedicinenews.org. Medical information in this column is provided as an educational service only. It does not replace the judgment of your personal physician, who should be relied on to diagnose and recommend treatment for any medical conditions. Past columns are available online at www.familymedicinenews.org.