Body Mass Index (BMI) - Topic Overview

Your body mass index (BMI) and waist size affect your risk of type 2 diabetes, high blood pressure, high cholesterol, and coronary artery disease. The following table shows the risk.

Body mass index (BMI) and the risk for diseases 1
Classification BMI Waist size and relative risk

Men: less than 40 in. (102 cm)

Women: less than 35 in. (88 cm)

Men: 40 in. (102 cm) or more

Women: 35 in. (88 cm) or more

Normal 18.5-24.9 - Increased risk
Overweight 25-29.9 Increased risk High risk
Obesity I 30-34.9 High risk Very high risk
Obesity II 35-39.9 Very high risk Very high risk
Obesity III (extreme) 40 or above Extremely high risk Extremely high risk

For Asian people, each risk category may include lower BMIs than those listed in the table.

A BMI under 18.5 is considered unhealthy. There is risk that you are not getting sufficient nutrition (malnutrition). Complications of malnutrition include anemia, nutrient deficiency, heart irregularities, loss of menstrual periods in women (amenorrhea), cavities, and osteoporosis.

WebMD Medical Reference from Healthwise
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.© 1995-2015 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.