Overweight/Obesity Definitions
Definitions of overweight, obesity, BMI, waist circumference, and WHR.
Definitions
Overweight: Increased body weight in relation to height. (Note: Overweight may not be due to body fat. It may also be due to increase muscle. An example may be professional athletes.)
Obesity: Excessive amounts of body fat or adipose tissue in relation to lean body mass.
Body Mass Index (BMI): A common ratio of weight-to-height. This formula is computed by dividing the square of a person's height in meters into a person's body weight in kilograms. Individuals with a BMI of 25 to 29.9 are considered overweight and an individual with a BMI of 30 or more is considered obese.
Waist Circumference: Measurement to assess abdominal fat content. Waist measurement for men greater than 40 inches and waist measurements for women greater than 35 inches are undesirable. (Note: If a person is under 5 feet in height or has a BMI of 35 or above, waist circumference standards used for the general population may not apply.)
Waist-to-Hip Ratio (WHR): The ratio of a person's waist measurement to hip measurement. Divide the waist circumference (distance around the smallest area below the rib case and above the belly button) by the hip circumference (distance around the largest extension of the buttocks). For both men and women, a 1.0 or higher WHR is considered at risk with a ratio of .90 or less being safe for men and a ratio or .80 or less is considered safe for women.
References
Stunkard AJ, Wadden TA. (Editors) Obesity: theory and therapy, Second Edition. New York: Raven Press, 1993. National Research Council. Diet and health: implications for reducing chronic disease risk. Washington, DC: National Academy Press, 1989. National Institutes of Health. Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults. Bethesda, Maryland: Department of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute, 1998. U.S. Department of Health and Human Services. Physical activity and health: a report of the Surgeon General. Atlanta: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention National Center for Chronic Disease Prevention and Health Promotion, 1996.