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Many people consider BMI as a standard health assessment tool. It is one of the most popular tools to measure body compositions and has used for a very long time.

What Is BMI?

BMI refers to Body Mass Index, which helps calculate your weight-to-height ratio. Developed by Belgian mathematician Lambert Adolphe Jacques Quetelet in the 1800s, BMI is still widely used by many health care practitioners to measure the health status of a person.

Though BMI comes with its own set of drawbacks, it can provide meaningful insight for people to understand their bodies and the risks associated with developing various diseases. Doctors may use these measurements and results to indicate which category you fall under and whether you have an increased risk for developing certain health conditions such as diabetes and heart disease.

You can even calculate your BMI online by clicking on the link below.

How to Measure Your BMI

If you are an adult 20 years or older, you can calculate your BMI using a calculator from the Centers for Disease Control and Prevention (CDC).  There is also a calculator available for children between the ages of 2 and 19.

Once you’ve calculated your BMI, you can check whether or not it falls under the normal range. The results can be categorized in the following manner:

  • Below 18.5 — Underweight
  • From 18.5 to 24.9 — Normal
  • From 25.0 to 29.9 — Overweight
  • More than 30 — Obese

What’s Considered a Normal BMI?

A normal BMI lies between 18.5 and 24.9. The higher your BMI the higher the risk of developing problems and conditions related to obesity, such as arthritis, sleep apnea, high cholesterol, high blood pressure, liver disease and diabetes.

People with BMIs in the obese category are at a higher risk of developing diabetes and cardiovascular diseases. Not everyone with a high BMI will suffer from these conditions, but the percentage of people with these diseases is higher among the obese category than normal and overweight categories.

How Can BMI Be Misleading and Inaccurate?

While BMI can provide a quick and easy method of calculating the health risks and overall health status of a person, it has downsides that make it an inaccurate and misleading indicator of health in certain cases. BMI does not consider the following factors:

Race and Ethnicity

People from different ethnic groups are grouped together for BMI calculation. The genetic and biological differences between muscle mass, weight and disease risk vary among people of different ethnicities and races. BMI does not account for these differences, which can lead to inaccurate and confusing results.

For instance, according to a study held in 2011, Black women with higher BMIs than white women have less metabolic risk. Other research suggests that even with lower BMIs, those of Middle Eastern or Asian descent have a higher risk of metabolic diseases than most people of European descent.


The concept of an ideal BMI may change as people become older. The elderly may have less muscle mass and more body fat. But being a little overweight may help them survive longer and protect them against certain diseases. It may help their bodies store reserves for fighting an illness. So, older people with BMIs in the overweight category may have less disease risk than those in the normal category.

Weight Distribution

BMI does not take into consideration the weight distribution of a body. The area where fat accumulates in the body plays a significant role in determining overall health. If a person has a pear-shaped body, where the fat builds up on the thighs and hips, it’s not considered potentially harmful. But, if a person has an apple-shaped body where the fat deposits around the waist, the person is more susceptible to type 2 diabetes and heart disease. So, two people with the same weight and height will have the same BMI but may have different health risks depending on their diet, lifestyles and fat distribution.

Body Fat Percentage

Body fat percentage is the percent of body fat tissue to the total mass of your body. Measuring body fat percentage is a more accurate health assessment because the disease risk is more correlated to body fat than any other factor.

BMI only considers the total body weight irrespective of whether the person has more muscle mass and less body fat. Due to this, some people with higher muscle mass may fall into the overweight category despite having an overall healthy body.

What Are Other Predictors of Health?

Many other factors can indicate the health and wellness of a person. Measuring these factors helps understand the risks of developing various diseases, such as diabetes, stroke and heart problems. There are five factors, namely:

  1. Waist circumference: Waist measurements higher than 35 inches (88.9 cm) in women and 40 inches (101.6 cm) in men indicate higher body fat in the abdominal region, which indicates a greater risk of developing obesity-related diseases.
  2. Blood pressure: Blood Pressure measures the pressure of the blood flowing against the artery walls. A blood pressure of 140/90mmHg is considered high and indicates a higher risk of heart disease.
  3. Blood cholesterol: The cholesterol levels in the blood indicate the amount of HDL (good) and LDL (bad) cholesterol. Excessive LDL in blood and overall cholesterolof 239 mg/dL indicate a higher heart disease risk.
  4. High blood sugar: Measuring blood sugar levels indicate the amount of glucose present in the blood. These amounts can help doctors screen for diabetes and prediabetes. If the blood sugar levels remain constantly higher than 125 mg/dL, it is known as hyperglycemia.
  5. Elevated triglycerides: Triglycerides are a type of fat molecule found in the bloodstream that increase when a person consumes more calories than they burn. Amounts of triglycerides over 200 mg/dL indicates higher disease risks in men and women.

The Bottom Line

Body mass index is a quick and easy health assessment tool to identify higher risks of developing diseases. As a single measure, BMI may not be able to accurately define these risks, as it does not consider the age, sex, body fat percentage and body shape of a person.

However, it is still a helpful starting point to measure and determine essential health conditions that become more likely when a person is obese or overweight. Using BMI with other metabolic factors like blood pressure, cholesterol, blood sugar and waist circumference can provide more accurate results for predicting overall health risks. Your doctors can better guide you whether your BMI shows accurate health results.

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If you think you may have a medical emergency, call 911 immediately, call your doctor, or go to the emergency room/urgent care.