How many times have you heard someone say, “I’m fat.”? Maybe you’ve even said or thought this to yourself on occasion. You wouldn’t be in the minority.

The word ‘fat’ can be confusing as it is one of our essential macronutrients, it’s used to describe the excess energy stored in our bodies (the stuff that giggles), and it’s also used to express how we feel about ourselves (not that ‘fat’ is a real feeling, but some do claim to feel the physical effects of excess energy storage).

So let’s do a simple reality check and determine if you are indeed ‘fat’.



Though there are multiple ways to do this, one of the quickest and simplest tools you can use to determine how much fat you are storing is the Body Mass Index (BMI). Though it doesn’t measure % body fat it’s a good estimate. BMI is actually a calculation that considers the weight and height relationship and determines one’s risk for health problems.

The World Health Organization (WHO) defines a healthy BMI range for men and women (adults of all ages) between 18.5 and 24.9. One is considered “overweight” if their BMI is between 25 to 29.9 and “obese” if their BMI is 30 or greater. Additionally, those who have a BMI under 18.5 are considered “underweight”.

The WHO estimates that there are over 1.5 billion adults that are either overweight or obese (about 34%) in the world.

By 2030 there may be more than 3 billion (about 68%)!

Your Body Mass Index does not only determine if you are ‘underweight’, ‘normal’, ‘overweight’, or ‘obese’, it’s also indicative of your risk for heart disease, type 2 diabetes and early death. The higher the BMI, the higher the risk; and even more so for some ethnic groups.

The lowest mortality rates are for those individuals with a BMI of 20-24.9. Those with a BMI over 42.5 have a 2.5 to 3x increased mortality rate and those with a BMI under 17.5 have a 2x increased mortality rate. Suddenly being ultra thin isn’t so attractive when you consider that it can take years off your life!

The BMI does have it’s limitations, however. It cannot be used to assess people who are very athletic. A body builder for instance, would have a high BMI because of his or her heavy muscle mass so this would not be an accurate way to assess health. Pregnant women also can’t be assessed by this method for obvious reasons. By the way, there are special charts for children that evaluate BMI.

So how do you calculate your Body Mass Index? All you need is your weight and height and a calculator (of course you can compute this by pencil too). Here’s the formula:

BMI  =  (Weight in Pounds x 703)  /  (Height in Inches)2

or you can simply enter your information into the Harvard School of Public Health’s BMI calculator and they’ll do the work for you:

Some researchers argue that waist circumference is more important than BMI but because height and weight are so easy to measure and are always recorded at the doctor’s offices BMI will continue to be a standard marker used for predicting disease risk. BTW—I’ll be discussing waist circumference in an upcoming article in the near future. Stay tuned!