ABSTRACT
The prevalence of obesity in the United States has increased dramatically over the last 20 years. Data from the 1999-2002 National Health and Nutrition Examination Survey (NHANES) show that 65% of the adult population in the United States is overweight, which is defi ned as having a body mass index (BMI) greater than 25 kg/m2, compared with 46% seen in NHANES I, conducted between 1971-1974 (Figure 37.1).5,10 The prevalence of obesity, defi ned as BMI greater than 30 kg/m2, has increased dramatically from 14 to 30% over the same time frame (Figure 37.1).10 Children are also affected, with the prevalence of obesity in children and adolescents up by 10% (from 6 to 16%) during this period (Figure 37.2). Based on prevalence data over the past 30 years, Foreyt and Goodrick11 predicted that the entire U.S. population will be obese by the twenty-third century. The World Health Organization (WHO) has declared overweight as one of the top ten risk conditions in the world and one of the top fi ve in developed nations.12
