Content Map Terms

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

Classification

BMI

Waist size and relative risk

Men: less than or equal to 102 cm (40 in.)

Women: less than or equal to 88 cm (35 in.)

Men: more than 102 cm (40 in.)

Women: more than 88 cm (35 in.)

Normal

18.5–24.9

—

—

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

Waist size cutoff may be lower for some people.

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.

Credits

Current as of: December 27, 2021

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Brian D. O'Brien MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Martin J. Gabica MD - Family Medicine
Rhonda O'Brien MS, RD, CDE - Certified Diabetes Educator