The second National Health and Nutrition Examination Survey found that 26% of U.S. adults, or about 34 million people aged 20 to 75 years, are overweight. The survey used a body mass index of 27.8 kg/m² or greater for men and 27.3 or greater for women to define overweight. Prevalence of overweight increases with advancing age and is generally much higher among black women than among white women. Women below the poverty line have a much higher prevalence of overweight between ages 25 and 55 years than women above the poverty line. Multivariate analysis indicates that for women race and poverty status are independent predictors of overweight. Hypertension, hypercholesterolemia, and diabetes are commoner in overweight persons than in persons who are not overweight. The relative risk of hypertension, hypercholesterolemia, and diabetes is greater in overweight adults aged 20 to 45 years than it is in overweight persons aged 45 to 75 years. This observation is consonant with mortality data, suggesting that being overweight during early adult life is more dangerous than a similar degree of overweight in later adult life.