Are You Overweight or Obese?

There may be better measures than BMI.

Posted Jan 21, 2016

StudioLaMagica/shutterstock
Source: StudioLaMagica/shutterstock

By now almost everyone is familiar with BMI (Body Mass Index). Although the formula is difficult to compute (weight in kilograms divided by height in meters squared) there are many online calculators that are easy to use. Using BMI, the cutoff for obesity is 30 or more while 25 to 30 is considered overweight.

The Body Mass Index was an improvement over the old height-weight charts that got started in the 1920’s and were based on life insurance company data. Although they were updated, and attempts were made to use a more representative sample (not everyone has life insurance), the tables were still difficult to use. BMI certainly is easier to use compared with the old tables but it’s hardly foolproof.

Arnold Schwarzenegger, at the height of his muscle-building career was six feet, two inches and weighed 257 pounds giving him a BMI of 33 but he was hardly obese. Pictures of him flexing his ample muscles showed very little fat tissue so why does he have an obese BMI? Simply because muscle tissue is heavier than fat so someone like Arnold who’s exceptionally muscular will have an inflated BMI. Another problem with BMI is that it may not be a very useful measure of health risks. Central adiposity, the internal visceral fat in your mid-section, rather than weight per se is associated with most of the medical problems attributed to obesity. Fat in the butt, thigh, arms etc. is not as dangerous as the fat in your gut.

From a health standpoint, it makes more sense to measure central adiposity rather than BMI. A simple procedure for measuring central adiposity is a low-tech tape measure. Use the tape to measure your waist (which probably isn’t the same as your belt size) to hip ratio. Measure the smallest circumference of your waist, usually just above the belly button, WITHOUT holding your breath in. Then measure your hip at the widest portion of your butt and divide the waist by the hip measurement. According to the World Health Organization obesity is a ratio greater than .85 for women and .90 for men.

You can also calculate your ideal weight range by using an updated version of the height and weight tables that include a rough measure of frame size. To measure frame size you take your thumb and middle finger (the longest finger) and circle your wrist. If the fingers touch you have a medium frame, if they don’t meet your frame is large, while if they overlap you have a small frame.

Rather than fixating on a specific BMI number, you can use these tools to find a healthy weight range that makes sense for you.