If you have been to your local shopping mall recently and are older than 20 years of age, you have witnessed the growing girth of many Americans. The United States is now the fattest country in the world! The U.S. government regularly surveys the American public to put numbers on the face of fatness. These surveys are called the National Health and Nutrition Examination Surveys (NHANES). Between 1960 and 1976, there was a slow rise in the number of Americans who were overweight. This rise was similar to the slow increase in overweight that occurred from the time of the Civil War (in 1860) through 1976 (Bray 1976a). Between 1976 and today, however, there has been a big jump in the number of overweight and obese Americans. The number has more than doubled between 1980 to 2002 (from 14.5% to 33.5% obese) (Ogden et al. 2007). The increased rate at which people are becoming fat has led some to label this an “epidemic” (the World Health Organization [WHO], the National Heart, Lung, and Blood Institute [NHLBI]).
Figure 1 shows this pattern of increase for three levels of body weight. The upper limit of normal is 25 body mass index (BMI) units, a number we will describe in more detail in Chapter 2. People above a normal BMI of 25 have increased from 45% of the population to over 60% today—a rise of more than one-third. A BMI of 30 in Figure 1 is the dividing line for obesity. The number of adults above a BMI of 30 has grown from 14% in 1960 to over 30% today—a 100% increase. The final line at a BMI of 40 defined the dividing line for the very obese. Very obese people were uncommon in 1960 but are now more than 5%—a more than 400% increase.