Understanding BMI vs. Body Fat Percentage
The BMI/Body Fat % dilemma. What is it? What does it mean? Should I know mine? I personally believe everyone should know their BMI. What is BMI? BMI stands for body mass index, if you didn’t already have some idea. BMI divides one’s weight by their height. It is used to predict a person’s risk of future disease. This is predicted based on whether the persons BMI is within a certain category. The higher the number the greater the risk for diseases like cardiovascular disease, cancer, and high blood pressure.
Example: Height- 5’4 or 64 inches. Weight- 139lbs
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Your BMI indicates whether you are within normal ranges, underweight, or overweight/obese. However, a person who is said to fall in the overweight category is not necessarily obese. Overweight refers to an excess amount of weight that includes all tissue, bone, muscle, water and fat. Obesity refers specifically to body fat. If you are wanting a general idea of where you stand, here is a simple formula! First, take your height in inches and multiply it by itself. Then, divide your weight in pounds by the answer from step one, and then multiply that answer by 703.
So using these numbers we can see a person weighing 139lbs with a height of 5’4 would have a body fat percentage of 23.85%. According to the chart below, a person with a BMI of 23.85% would be within normal ranges when comparing weight relative to height. In my personal and professional opinion, knowing your BMI can help you realize a change in your health and lifestyle may be needed.
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For those of us who want to know more about the relation of body fat to body weight, you must calculate your body fat percentage. Unfortunately, BMI is not enough to measure your body fat percentage because it is limited. BMI does not account for a person’s gender, age, or build. A body builders BMI can appear to be overweight or obese because of their athletic build. Muscle is more dense than fat. Body fat percentage measures the fat on your body relative to lean body mass, which is comprised of: bone, brain, organs, and skin etc. Having an idea of your body fat percent vs. only knowing your BMI allows you to determine exactly WHAT percent of your bodyweight for example, is actually “body fat”. Women naturally have more body fat than men and older people tend to have more body fat than younger people. This is where simply only measuring your BMI fails us. Women who fall in the 10%-12% range has an essential body fat make-up, commonly seen in fitness models and fashion models. Women who fall in the 14%-20% range have an athletic body fat make-up, commonly seen in gymnasts or dancers. Women who fall in the 21%-24% range have a “fit” body fat make-up, commonly seen in women basketball players, soccer, or softball players. A body fat percentage in the 25%-31% range has a body fat make-up that is “acceptable” but could be at risk of being too high if bad habits and unhealthy eating habits persist. This range is common and seen in those who are moderately active. Maybe they have a physical job, work out 1 or 2 times a week, or participate in active or athletic type events (color run) from time to time.
If we were to really hone in on practicing better health habits and changing our mindset on what “good nutrition” (as discussed in my previous article: What is Good Nutrition?) is, we would see our body fat % drop/improve. If you haven’t already assumed, any body fat percentage of 32% or more is obese. Fear not! There is always a way to make small changes daily that will improve your weight, body fat percentage, and overall health in the long run.
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The best way to have your body fat measured is with the skin fold test using a tool called a caliper. It may be easier to entrust your personal trainer to gather these measurements for you as you would need to pinch at least an inch of your skin in these areas: Pectoral (chest), Mid-Auxillary (arm-pit), Suprailiac (pelvis/hip area), Abdominal (belly button area), Quadriceps ( thigh), calf, Subscapular (shoulder blade), and tricep. Once these areas of pinched skin have been measured and logged with a caliper, your trainer will calculate what your body fat will be. The caliper measures the skinfold (a fold of skin and fat) because approximately 50% of the body fat is made up of subcutaneous tissue (under the skin) and follows that the thicker the skinfold the greater amount of fat the person is carrying.
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If you do not have a trainer to measure body fat using this method, doing it yourself can be a bit complicated when plugging in your measurements to the mathematical equation for body fat %. We can visit this equation on a later post, but for now I would say getting educated about your BMI and/or Body fat percentage is important! Simply starting with figuring out your BMI is a great start to creating awareness about your weight and whether you are in a healthy range or not. Remember,if you want change to occur in any aspect of your life, especially in the health and fitness area, consistency is key!
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Sources:
Frederick C.Hatfield - International Sports Sciences Association – 2008 Livestrong.com Jessica Bruso https://www.livestrong.com/article/188526-what-is-the-typical-body-fat-percentage-for-an-elite-athlete/ How to calculate BMI https://www.thecalculatorsite.com/articles/health/bmi-formula-for-bmi-calculations.php |
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