Body mass index, known as BMI, is a commonly used indicator of potentially harmful weight problems.

The potential risks of being obese or overweight have created a major health problem in the United States today, claiming almost the same number of lives as cigarette smoking, according to data recorded since 2000 from the Centers for Disease Control and Prevention. Not only do these weight ranges increase risk for chronic diseases such as heart disease, diabetes, stroke and cancer, they’re also hard on hip and knee joints that are needed to support that weight. In addition, the extra weight may lead to psychological disorders such as depression.

How do you know if you are overweight or obese? Health professionals rely on two simple tools.

Body Mass Index (BMI)

The BMI is a number that relates body weight to height and is a commonly used indicator of body fat. You can calculate the formula as:

Weight (pounds) x 703 divided by [Height (inches)]^2

or in metrics: Weight (kg) divided by [Height (meters)]^2

Or you can use any of a number of online BMI calculators by inserting your height and weight or electronic hand-held devices that send electrical signals through your body to measure your resulting BMI (people with pacemakers are advised not to use these devices). The results will place you in one of the following categories that measure risk of chronic disease:*

Typically, the higher ones BMI is, then the higher the amount of ones body fat. The relation between body fat and BMI differs with age and gender. For example, women are more likely to have a higher percentage of body fat than men for the same BMI.

BMI isn’t perfect it can overestimate body fat in athletes and others who have a muscular build, and may underestimate body fat in older persons and others who have lost muscle mass. BMI is not appropriate for pregnant or lactating women, along with those over the age of 65.

Waist Circumference

The second tool health professionals will use is a tape measure around your middle, placed just above your hip bones after you breathe out. Accordingly, if the extra weight is around your waist, your risk for chronic diseases like heart disease and diabetes is even higher. That risk continues to climb for waist sizes greater than 35 inches in women and greater than 40 inches in men.

If you find that either of these measurements put you at risk for chronic disease, talk to your doctor and then reach out to a registered dietitian who can help you adjust your diet. Visit to find a registered dietitian near you.

Bethany Thayer, MS, RDN, is a registered dietitian nutritionist and National Spokesperson for the Academy of Nutrition and Dietetics. Passionate about transforming lives and communities through health and wellness, Thayer develops strategies, programs and policies for employer groups to help improve the health of their employees.