Here’s an article I found a while ago that describes normal weight obesity as an emerging risk factor for heart and metabolic problems:
More than half of American adults considered to be of normal body weight in the United States have high percentages of body fat — more than 20 percent for men and 30 percent for women — as well as heart and metabolic disorders, according to shows new research from Mayo Clinic. The finding contradicts widely held beliefs that maintaining a normal weight automatically protects against conditions such as high levels of circulating blood fats and a tendency to develop metabolic syndrome, which often leads to type 2 diabetes.
First, some background on the Body Mass Index. It was devised in the 19th century by Adolphe Quetelet as the “Quetelet Obesity Index”. In the 1980s, it became the international standard for comparing weight to an objective standard. It’s the measure Mayo Clinic researchers used in the earlier study. To calculate your BMI, divide your weight in kilograms by your height in meters, squared. The BMI was designed “as a simple means of classifying sedentary (physically inactive) individuals with average body composition.”(2) Please note that this was not intended as a one-size-fits-all measure. It was designed for a very specific population and has now been put to use for everyone.
But we have to ask, “what is a normal weight?” According to BMI, I’m supposed to be between 144 and 175 pounds (3), but I can’t remember when I was under 180 pounds and I’m currently around 185 (BMI 26.5), where they’ve been for the past few years. Since few people would guess that I weigh so much and maintain a low body fat percentage, it seems ridiculous to think I’m “overweight,” but that’s what a measurement based solely on weight versus height will give you. . I can only imagine what I would look like at 144 pounds or even 160 pounds. The upper limit of that “healthy” range may be doable if you were willing to sacrifice some muscle. So should I strive to be “normal” or stay at the weight my body naturally gravitates to when I’m not trying to alter it by adding or losing mass?
So once you’ve calculated your BMI, what do you do with it? Throw away. It’s useless. Go stand in front of a mirror and jump. Do things move and you’d rather they didn’t move? Do your clothes fit you how you want? Do you have the muscle definition you would like to have? Those should be your measurements, not what the scale says. If you wear your college jeans, which seems to be a feminine marker, why does it matter what the scale says?
Here’s a fun thought: Most NFL linebackers are classified as obese, just like most other professional athletes. Many older people with very little muscle mass qualify as “healthy weight.” Those are the skinny and fat people that the previous article refers to and it does not affect only the elderly.
There really is too much focus on weight in our culture, especially by women. That’s the problem with BMI, it focuses solely on weight versus height. It does not take into account muscle mass, waist circumference or percentage of body fat. Thinking of “normal weight” made me think of a post by Alwyn Cosgrove some time ago called “The Fat Sucking Machine” (4):
If only we had a magic fat loss machine where you went in and pushed a button and walked out EXACTLY how you always dreamed you would look and feel: the exact dress or pant size you wanted, with muscle definition and tone. you want, with the percentage of body fat you want – you can see your abs (if that’s what you want), etc., etc.
Would you be interested? Of course you would!
But what if the side effect of the fat loss machine is that it increases bone density and muscle density by 100%. So while he looked and felt better than ever, the scale is 50 pounds taller than ever. So, for example, a 150 pound would look amazing, but it would weigh 200 pounds…
So what is the value of the BMI? At the individual level, absolutely none. It is a statistical tool that only has a small value and is for use in a large population, so that very muscular athletes with a BMI of 28+ are averaged with skinny and fat people who have the mentioned BMI of 18-25 with body fat percentages of 25%. If what worries you is the weight, I have the perfect solution for you. Cut off your leg. You just lost a good 1/5 of your body weight. Are you satisfied? Most of the time, weight loss attempts result in a smaller version of the same body, twenty pounds lighter, but still looking like a pear.
So what are the best measures to check? Body fat percentage is a great start. For men, a normal range is the mid-teens. For women, between 20 and 20 years old. Women get the pleasure of carrying more fat to nourish those growing babies. Obviously athletes will be in lower percentages, but for the average person, those are good ranges. Waist circumference, or better yet, waist-to-hip ratio is another that can help determine what kind of weight you’re carrying. However, the easiest measure is the mirror test. Look in the mirror. Jump up and down. You like what you see? Do your clothes fit you better or worse than last week? If the answer is “better” then move on. If the answer is “worse”, go back to the drawing board.
Sources:
(1) The history of BMI
(2) Body mass index
(3) Tables of normal weight for height (1958)
(4) The fat sucking machine. [http://alwyncosgrove.blogspot.com/2008/02/fat-sucking-machine.html].