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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 diseasesfootnote 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.

Related Information

References

Citations

  1. National Heart, Lung, and Blood Institute, 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.

Credits

Current as of: December 27, 2021

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

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