The Truth About BMI and Alternatives to BMI Measurement

You consider yourself to be pretty healthy, but according to your Body Mass Index (BMI) you overweight or obese - what's the deal?!


This is a more common scenario than you think. So, what exactly is your BMI and what does it tell you? Keep reading to learn more


Put simply, BMI is a calculation using a person's height and weight to categorize them as a healthy or unhealthy weight. Most people use an online calculator to find out their BMI, but you could to the math yourself with this formula: weight (lb) / [height (in)]² x 703


Generally, a higher BMI is considered less healthy than a lower BMI. General BMI guidelines are:


Below 18.5: Underweight

18.5 - 24.9: Normal

25 - 29.9: Overweight

30 and above: Obese


The Problems with BMI


BMI has come under some scrutiny recently for a few reasons. First, it does not take into account how much fat and how much muscle a person has.


So, for example, two men that are 5'10 both weigh 170 pounds. They would have the same BMI - 24.4. However, one of those men could have 5% body fat and the other could have 15% body fat.


We know that having excess body fat can lead to negative health outcomes. So, the man with a higher body fat is at higher risk of health problems even though his BMI is within the normal range.


Another issue with BMI is that it does not account for differences in male and female body composition. Women naturally have a higher percentage of body fat and they carry excess weight in different areas of the body than men do. There are too many differences in male and female body weight and composition to use the exact same calculation for everyone.


BMI is also a poor indicator of health for people of significantly above or below average height. For taller individuals, the BMI calculation does not account for the fact that they may have more skeletal weight than their average-height counterparts. For shorter individuals, BMI may be a little too forgiving.


BMI is a convenient, simple way to track data for large groups of people. It can offer a general overview of the number of overweight and obese people in the population. But on an individual level, there are better ways to measure your health.


Alternatives to Using BMI


If you're ready to abandon BMI as a way to measure your own health, here are a few alternatives.


Circumference Measurements


If you have a tape measure at home, you can use various circumference measurements to see how you compare to others in your age, height, and weight range (although this data may not always be easy to find.)


You can use it to measure personal progress. if you notice that you haven't been losing weight but your clothes are fitting better, it's possible that your body composition is changing. You can find out by regularly measuring the circumference of different areas of the body to see whether you've made progress.


The most common areas of the body to use circumference measurements are hips, waist, and chest.


Waist to Height Ratio


Your waist to height ratio is a measurement of localized fat in your midsection. Using waist to height may help predict whether you are at risk for certain health conditions.


To find out, measure the circumference of your waist and divide it by your height. A"healthy" weight to height ratio is about 0.5.


The waist to hip ratio is another measurement used to measure localized excess weight. You can find more info on waist to hip ratio here.


Skin Fold Test


Finally, a skin fold test can help measure body composition. The skin fold test uses a caliper device to pinch areas of the body to get a reading of the fat in that area.


A medical professional or a personal trainer may have access to calipers like this and they use specific calculations to determine overall body fat percentage. Body fat percentage may be a better indicator of health outcomes than BMI alone.