How to measure your body mass index – and what it means for your health

Nearly 40 percent of U.S. adults are obese

Nearly 40% of U.S. adults are obese, according to a 2018 study.
Ehimetalor Unuabona/Unsplash.com

Obesity rates have been rising in the United States for several decades, a trend that has public health officials concerned given the serious health risks associated with the condition. 

About 93.3 million people in the United States are obese – nearly 40% of the adult population – according to a 2018 study.

Obesity is considered a major risk factor for various conditions, including type 2 diabetes, cardiovascular disease, high blood pressure and cancer. Almost 365,000 deaths each year can be attributed to obesity, according to Harvard Health


RELATED STORY: Pennsylvania youth rank among the most obese the country


One way to determine if the little extra padding around your middle is putting your health at risk is to measure your body mass index, or BMI. Body mass index is the primary way doctors measure whether patients are at a healthy weight. 

To calculate it, you can simply input your height and weight into an online BMI calculator like this oneA BMI between 25 and 29.9 is considered overweight. A BMI of 30 and over is considered obese. Anything beneath 18.5 is viewed as underweight. 

Waist circumference is another way to determine your risk for obesity and its related health issues. For women, a waist size larger than 35 inches is of concern. For men, it's a waist larger than 40 inches. 

Even losing few pounds can improve cardiovascular health, according to the American Heart Association. Not only can the body circulate blood in a more efficient manner, but it can also manage fluid levels better.

Additionally, losing weight can help people who are obese better manage high blood pressure as well as high cholesterol and triglyceride levels. Obesity also increases the risk of heart disease and stroke. 

Still, BMI only can tell us so much about our health. According to the National Heart, Lung, and Blood Institute, it "may overestimate body fat in athletes and others who have a muscular build" or it "may underestimate body fat in older persons and others who have lost muscle."

Dr. Robert H. Shmerling, of Harvard Health, cautions that BMI is not a measure of patient's total healthThere are people with a high BMI who are healthy and people with a normal BMI who are not, he says. Still, Shmerling finds it a useful tool because a high BMI is linked to increased risk for various health conditions.  

The Centers for Disease Control and Prevention also does not consider BMI a diagnostic tool for disease risk. It recommends making time for regular health evaluations from a trained healthcare provider.