Thursday, March 3, 2011

Obesity Is Not the Problem


Obesity is Not the Problem.
A BMI > 30 is the Problem.

     People often come in to see me for care of their diseases. I routinely ask them what chronic medical problems they have, and they tell me all about their high blood pressure, diabetes, thyroid problem, and osteoporosis, etc. They usually don't think to mention the fact that they are significantly overweight. This is very understandable. Obesity is an unpleasant word to use about anyone. Yet our nation's economy depends heavily upon being able to sell junk food to almost everyone, with obesity as an obvious natural result. Therefore  I propose getting rid of the word obesity, at least as a medical term.
     The problems with it as a medical term are that it is too vague. The term "obesity" is generally used to mean someone is 20% or more overweight. Unfortunately, most people do not know their ideal weight, and, even if they did, it is no simple matter for most of us to multiple it by .2 and add it to our ideal weight in order to determine if we are obese. Who does that? Furthermore, some people are finicky and refer to themselves as overweight at a mere 10% over ideal body weight, while others at 30% over ideal body weight consider themselves normal because everyone else in their family is that way. "Normal" is relative after all. And, of course, in our society "obese" is a stigmatizing word that is used to attach a label to people as though they were all of the same nationality and ought to be blamed for a host of our country's ills. All of this is unhelpful.
      The good news is that obesity itself is not a disease, and its health hazards have been overstated. The trend in the medical profession has been away from classifying people as obese. Instead the clinical measure has become Body Mass Index (BMI). This number takes your weight (in kilograms as it turns out) and adjusts it for your height (in meters); the specific formula is: BMI= weight(kg) / height(meters)^2 (squared)
     There are a couple of really handy things about this number: (1) With the new electronic medical records that all health systems use, your weight and height can be automatically converted into this single number without anyone having to do any math; and (2) It turns out that there is a nice, simple dividing line for separating all those people whose weight, however much over ideal body weight it may be, is not a problem clinically from all the rest who have a significant, in fact, major medical problem.
     The magic number is 30 (kg/m^2). If your BMI is less than 30, your weight is not a medical problem. The experts define a normal BMI as between 18 and 25, but being over 25 is not associated with any significant increase in medical complications until you hit 30. A BMI > 30, however, is associated with significant increases in the risk of developing diabetes, high cholesterol, hypertension, heart disease, stroke, and dying. It is a real problem.
     Thus, when you come in to my office, I will always check your recorded height and weight to calculate your BMI. I will tell you if it is greater than 30, and I will record it in your chart as a medical problem, just as I do for hypertension and diabetes. And we will have a discussion about what you can confidently do to bring it back down under 30. We don't have to shoot for your perfect weight. We just have to get your BMI down under 30. This is a much easier goal to accomplish. For most people it can be achieved with an increase in exercise and conscious eating to lose around 10 pounds.

     Here's a handy little tool to calculate your own BMI. Let me know if it is over 30, and we can do something about it.