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BMI Vs. Body Fat %

The body mass index is calculated simply by using the height and weight.  A BMI less than 25 is considered normal, a BMI between 25 and 30 defines being “overweight”, a BMI between 30-40 is considered “obese” and a BMI over 40 is called “morbid obesity”.

Percentage body fat is calculated by taking the weight and dividing this number by the total weight.  A “normal” percentage body fat is defined as less than 25% for a male and less than 30% for a female.

Let’s take a person that is 5 feet 10 inches and weighs 220 pounds.  The BMI of that person is calculated to be 31.6; therefore, this person is considered “obese”.

Now, we will proceed with looking at 2 different people…one is an NFL football running back that stands 5 feet 10 inches and weighs 220 pounds and the second person is a 56 year old accountant that is similarly 5 feet 10 inches and 220 pounds.  Both have exactly the same BMI of 31.6 and both are in the category of “obese” as per BMI definitions.  

Here is a huge difference however.  The football player most likely has a body fat % of less than 10% whereas the accountant will probably have a body fat % well over 30% and there is a good chance this % may be well into the 40’s.  The football player is a well-toned, well-sculpted athlete that is incredibly healthy and has an incredibly low risk of developing obesity related co-morbidities such as diabetes, cancer or heart disease.  The accountant (assuming a high % body fat) will be very much at risk for developing life-altering diseases based on the weight.

The point:  Do not focus only on weight/BMI as a marker for developing serious medical issues.  The much more important factor is body composition, i.e. how much fat % is present as well as muscle mass.  The goal for weight control is not necessarily a BMI number but rather, a healthy body fat %.  Eating lots of protein, minimizing carbs, avoiding alcohol and exercising with strength training will all contribute to having the body fat % drop dramatically.  

We offer FREE body scans in our office!  Please take advantage of this so you can follow your body composition and take the steps needed to get that body fat % down.

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