Statisticians rely on BMI, why YOU should not!

It is not uncommon for your doctor to do a little simple math with your height and weight and come up with a risk factor or recommendation for you. The equation behind the BMI is straightforward:

BMI = Weight in Kilograms
(Height in Meters) x (Height in Meters)

The results are interpreted based on the table below:

BMI	Weight Classification
Less than 18.5	under weight
18.5 – 24.9	normal
25 – 29.9	overweight
30 and above	obese

There are some positive features of BMI: it is cheap, easy to perform and used in many large studies. But it doesn’t always tell the real story. BMI is used in large research trials which deal with populations – but you are an individual. What applies to a group may not apply to a single entity. An example of this is to look at the BMI of two very different males. They are both 5’10 and 190lbs with a BMI of 27.3 –overweight based on their BMI. One of these guys lifts weights on a regular basis; the other’s idea of exercise is to hoist a beer. In short, one is muscular while the other carries more fat. BMI does not take lean muscle mass into account. Having a higher than average muscle mass results in a BMI that suggests overweight or even obese in healthy active people. BMI can also classify a slim, inactive person as being healthy when in fact they have very low muscle mass and a higher than average fat mass.

So, if BMI doesn’t tell the story, how do we assess health risks? Answer: Get your body fat measured directly. A DXA total body scan provides not only a value for the % body fat, but provides the actual number of grams of lean mass, fat mass and bone mass in the body and in select areas within the body. If you want to know how you as an individual measure up get tested – if you’re just wondering where you fit relative to a population of thousands, then BMI is the tool for you.

To read more about why we should not rely on BMI read: "When Determining Who's Fat: Is BMI bunk?

To learn more about Bodycomp's DXA total body scan visit our website: www.bodycomp.ca