Body Mass Index (BMI)

The BMI, which describes relative weight for height, is significantly correlated
with total body fat content. The BMI should be used to assess overweight and obesity
and to monitor changes in body weight. In addition, measurements of body weight alone
can be used to determine efficacy of weight loss therapy. BMI is calculated as weight
(kg)/height squared (m2).

To estimate BMI using pounds and inches, use: [weight
(pounds)/height (inches)2] x 703.

An estimated 97 million adults in the United States are overweight or obese, a condition that
substantially raises their risk of morbidity from hypertension, dyslipidemia, type 2 diabetes,
coronary heart disease, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory
problems, and endometrial, breast, prostate, and colon cancers. Higher body weights are also associated
with increases in all-cause mortality. Obese individuals may also suffer from social stigmatization
and discrimination. As a major contributor to preventive death in the United States today,
overweight and obesity pose a major public health challenge.

Overweight is here defined as a body mass index (BMI) of 25 to 29.9 kg/m2 and obesity as a BMI
of ³ 30 kg/m2. However, overweight and obesity are not mutually exclusive, since obese persons
are also overweight. A BMI of 30 is about 30 lb overweight and equivalent to 221 lb in a 6'0"
person and to 186 lb in one 5'6". The number of overweight and obese men and women has
risen since 1960; in the last decade the percentage of people in these categories has increased to
66.7 percent of adults age 20 years or older. Overweight and obesity are especially evident in
some minority groups, as well as in those with lower incomes and less education.

Who is at Risk? All overweight and obese adults (age 18 years of age or older) with a
BMI of ³25 are considered at risk for developing associated morbidities or diseases such
as hypertension, high blood cholesteral, type 2 diabetes, coronary heart disease, and other
diseases. Individuals with a BMI of 25 to 29.9 are considered overweight, while individuals
with a BMI ³30 are considered obese. Treatment of overweight is recommended
only when patients have two or more risk factors or a high waist circumference. It should
focus on altering dietary and physical activity patterns to prevent development of obesity
and to produce moderate weight loss. Treatment of obesity should focus on producing
substantial weight loss over a prolonged period. The presence of comorbidities in overweight
and obese patients should be considered when deciding on treatment options.

CLASSIFICATION OF OVERWEIGHT AND OBESITY BY BMI

                                               Obesity Class                         BMI (kg/m2)