Overview
Overview Body mass index (BMI) (Figure 1) can help you see if your weight is raising your risk for health problems. It uses a formula to compare how much you weigh with how tall you are.
A BMI lower than 18.5 is considered underweight. A BMI between 18.5 and 24.9 is considered healthy. A BMI between 25 and 29.9 is considered overweight. A BMI of 30 or higher is considered obese. If your BMI is in the normal range, it means that you have a lower risk for weight-related health problems. If your BMI is in the overweight or obese range, you may be at increased risk for weight-related health problems, such as high blood pressure, heart disease, stroke, arthritis or joint pain, and diabetes. If your BMI is in the underweight range, you may be at increased risk for health problems such as fatigue, lower protection (immunity) against illness, muscle loss, bone loss, hair loss, and hormone problems.
BMI is just one measure of your risk for weight-related health problems. You may be at higher risk for health problems if you are not active, you eat an unhealthy diet, or you drink too much alcohol or use tobacco products.
Figure 1 - Body mass index (BMI) for adults Adapted from: U.S. National Heart, Lung and Blood Institute; U.S. National Institutes of Health (2000). The Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. (NIH Publication No. 00-4084). Available online: http://www.nhlbi.nih.gov/guidelines/obesity/prctgd_c.pdf
Use the chart to locate your height and weight. The shaded regions on the chart correspond to weight ranges based on body mass index (BMI).
For adults 20 years and older:
A BMI below 18.5 (light blue) is considered underweight. A BMI of 18.5 to 24.9 (green) is considered healthy. A BMI of 25 to 29.9 (yellow) is considered overweight. A BMI of 30 to 39.9 (red) is considered obese. A BMI of 40 or higher (purple) is considered extreme obesity. Keep in mind that BMI is only a guide. It is not a tool to determine ideal body weight. It is a tool to help you see whether your weight is increasing your risk for disease. BMI does not work as well for people who are very muscular or those who have little muscle. A muscular person may have a high BMI but still have a healthy level of body fat. A person with very little muscle may have a normal BMI but have unhealthy levels of body fat.
If you are Asian, your health may be at risk with a lower BMI.
A person who has a large change in BMI, even if he or she is not overweight or underweight, should be evaluated to find the cause.
Current as of: April 30, 2024
Author: Ignite Healthwise, LLC StaffClinical Review Board
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Current as of: April 30, 2024
