Is Your BMI Really A Good Measure Of Your Health?

What is BMI, and is it a good measure of your health? BMI—body mass index—uses your height to weight ration to determine the amount of body fat you have. The more body fat, the more potential there is for poor health. However, it’s not always a true picture or the final verdict. For instance, people with a great deal of muscle mass might appear on paper to be overweight, since a cubic inch of muscle tissue weighs more than a cubic inch of fat tissue. However, that’s simply not true. BMI also doesn’t take account bone density or the composition of a person’s body.

With BMI, it’s all about height to weight ratio.

BMI is a shorthand way of a doctor assessing your fitness. However, it’s only one tool. If your weight is 120 pounds and you’re at your ideal weight, it doesn’t necessarily mean you’re fit. It simply means that at your height, your weight is the same other healthy people your height. Your gender and frame makes a difference. The height to weight ration is converted to a number and anyone with a BMI that’s between 18.5 and 24.9 is at an ideal weight, while higher up to 29 is overweight. People with a BMI of 30 or higher are obese.

Another flaw with BMI is the role bone structure plays.

You’ve heard of people being “big-boned.” That’s really a thing. Some people have a smaller bone structure, which means their bones don’t weigh as much, so they don’t either, but they may have more fat than someone who has bigger bones does. Even the difference between having a longer trunk and shorter legs can make a difference in your weight and how you look. Men have more muscle mass, so they’ll weigh more than women. Even if people are exactly the same height and weight won’t look alike, since one may have more muscle tissue.

The use of BMI is a quick way to help physicians, but not the last word about your health.

It only takes a second to check your height and weight and convert that to a BMI on the chart, but it definitely isn’t the last word about your health. Physicians use it to identify potential problems, such as type 2 diabetes, heart disease, breathing problems and sleep apnea, which are face by people with higher BMI. Doctors use it as a starting place, with their personal observation as another factor.

  • One important factor that’s being used more frequently is waist circumference. People with a higher waist circumference, even when their BMI is normal, face more potential for illness, like diabetes. For men, 40.2 inches and for women 34.6 inches has the greater chance of diabetes.
  • Another new technique that works well is called RFM— relative fat mass index. It uses a ratio of waist measurements to height. For men the formula is 64 – (20 x height/waist circumference) and for women 76 – (20 x height/waist circumference).
  • A very accurate way, but quite costly way also, is an MRI scan. Underwater weighing also gives a clearer picture, plus identifying bone density, fat and volume.
  • One reason more muscular people often show as being overweight, when they aren’t, is because a cubic inch of muscle mass weighs more than a cubic inch of fat. It’s one of the biggest flaws in using BMI.

For more information, contact us today at Habitat Health and Fitness

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