Body Mass Index (BMI): What Is It and Why Is It Important?


If you’ve ever tried to lose weight, chances are you came across the term body mass index, or BMI for short. But what exactly is body mass index, and why is it important for your health journey?

Body mass index is a simple screening tool that helps determine if you are at a healthy weight for your body size. BMI isn’t an exact measurement, but it gives a good estimate of how much fat your body carries. Because of this, body mass index is often one of the first measurements your doctor looks at to assess your overall health and wellbeing.

But you don’t have to wait until your next doctor’s appointment to figure all of this out; you can calculate your own BMI with a simple formula. Knowing your body mass index, and understanding the steps you can take to get to a healthy BMI, is one of the most important ways you can improve your health and protect yourself against disease.

An Easy BMI Calculation Formula

The BMI calculation formula is easy. All you need is your height and weight.

BMI calculation formula:  703 x [height (inches) squared / weight (lbs)] = BMI

Or if you aren’t in the mood for math, use the chart below to easily find your body mass index. To calculate your BMI using this chart, follow the line from your weight (across the top) down to your approximate height (along the left side).

According to the National Institutes of Health, a healthy body mass index for adults falls somewhere between 18.5 and 24.9. A BMI of 25 or above is considered overweight and a BMI of 30 or more is considered obese.

The Importance of a Healthy BMI

If your BMI is higher than the normal range, you aren’t alone. A 2018 CDC survey found that over 42% of adults in the US are considered obese. But this trend comes with serious consequences. Studies show that a high BMI increases your risk of developing a number of diseases and serious health conditions. It also increases your risk of premature death.

A high BMI puts you at risk for developing:

  • Diabetes
  • Heart diseases
  • Stroke
  • Certain cancers including breast, colon and prostate
  • Osteoarthritis
  • Sleep apnea and breathing problems

The good news is that you aren’t bound by the number on your BMI calculation formula. Losing weight and decreasing your BMI significantly lowers your risk of developing many serious health conditions. One study by Washington University School of Medicine found that people who lost just 5% of their body weight decreased risk factors for heart disease, diabetes and stroke. And researchers at Johns Hopkins found that, if you are pre-diabetic, losing 5-10% of your body weight lowers your risk of developing type 2 diabetes by 58%.

In addition to these benefits, losing weight and decreasing your BMI improves your lung function, increases energy, and has been shown to reduce symptoms of depression in some patients. By lowering your BMI, you have the power to make a change and improve your future.

Achieving a Healthy Body Mass Index

Getting to a healthy body weight is one of the best steps you can take on your journey to health and wellness. But many people need a little help with their weight loss goals. If you are concerned about your BMI, I encourage you to speak to me or one of the nurses at our clinics. Together, we can map out a plan that is right for you.

Hales, C.M., et al. Prevalence of Obesity and Severe Obesity Among Adults; United States, 2017-2018. NCHS Data Brief No. 360. (2020).

Johns Hopkins Medicine. People With Pre-Diabetes Who Drop Substantial Weight May Ward Off Type 2 Diabetes. Johns Hopkins News Release. (16 July 2013).

Magkos, F., et al. Effects of Moderate and Subsequent Progressive Weight Loss on Metabolic Function and Adipose Tissue Biology in Humans with Obesity. Cell Metabolism Clinical and Translational Report, 23(4) 591-601 (2016).

National Heart, Lung, and Blood Institute. Managing Overweight and Obesity in Adults: Systematic Evidence Review from the Obesity Expert Panel. (2013).

Society for the Study of Ingestive Behavior. Weight Loss Improves Mood In Depressed People, New Research Shows. ScienceDaily (29 July 2009).

Torgan, C. Benefits of Moderate Weight Loss in People with Obesity. NIH Research Matters (2016).

World Health Organization. Global Health Observatory Data: Mean Body Mass Index. Retrieved 9.3.20 from