Obesity is associated with many significant health problems, including high blood pressure, diabetes, heart disease, premature death and decreased quality of life. Healthcare providers should screen for obesity using the body mass index, which the Task Force said is a valid and reliable screening test. People with a BMI between 25 and 29.9 are considered overweight, and those with a BMI of more than 30 are considered obese. BMI is calculated either as weight in pounds divided by height in inches squared multiplied by 703, or as weight in kilograms divided by height in meters squared. An on-line BMI calculator can be found at http://www.cdc.gov/nccdphp/dnpa/bmi/calc-bmi.htm.
Clinicians may also consider measuring patients for centrally located body weight, which is independently associated with cardiovascular disease, using waist circumference as a measure. Men with waist circumferences greater than 40 inches and women with waist circumferences greater than 35 inches are at increased risk for cardiovascular disease, but these measurements may be inaccurate for people with a BMI greater than 35.
Over the past 40 years, prevalence of obesity among adults in the U.S. has increased from 13 percent to 27 percent. The proportion of adults considered to be overweight has increased from 31 percent to 34 percent. Obesity is more common in women, but men are more likely to be overweight. Obesity is especially common in African Americans, Native Americans, Native Hawaiians and some Hispanic populations.