Epidemic of Obesity in the United States

I’ve heard people say that there is an “epidemic” of obesity. What does that mean? How bad is the problem in the United States?

The World Health Organization has noted that there are 1 billion overweight adults and 300,000,000 obese adults on a planet of 6 or 7 billion people. There has been about a threefold increase in obesity rates in the developed world (North America, Europe, etc.) compared with 1980. Increases are seen in developing countries as well.

The U.S. Surgeon General has indicated that over 12 million American children (17% of all children in the United States) are overweight. The prevalence of obesity in 2 to 5 year olds has gone from 5% in the period between 1976 and 1980 to 13.9% in 2004. The prevalence of overweight children has doubled and of overweight adolescents has tripled since 1980.

Some 15% of children aged 6 to 19 are obese. The numbers are higher in Mexican-American and African-American adolescents. The data are even more striking if one compares the rates to the 1960s, when only 4% of kids 6 to 17 years old were overweight. Because up to 75% of overweight children become overweight adults, this is not just an isolated problem that goes away as children age.

In a study published in 2009, researchers studied over 8,500 U.S. 4 year olds born between 2001 and 2005. They found that over 18%—about 1 in 5—were already overweight. Differences were noted in various ethnic groups: 31% of American Indian/Native Alaskans, 22% of Hispanics, 21% of Blacks, 16% of Whites, and 13% of Asian 4 year olds were obese. It is shocking that obesity is seen so early—even before these children started school.

At a recent Centers for Disease Control (CDC) conference, it was noted that in adults, the prevalence of obesity in the United States increased 37% from 1998 to 2006. The “average” American is now 23 pounds overweight. The cost of treating obesity increased from
$74 billion in 1998 to $147 billion in 2008.

The reasons for this appear to relate to the changes in the way we live. Higher incomes seem to have produced a change in the types of food we consume, moving from complex carbohydrate foods (fruits, bread, and pasta) to foods high in fat (particularly saturated fat) and sugar.

People are also doing less physical work, as machines now do many tasks that humans used to do. In addition, the work week has shortened, and there is more leisure time, as well as an increase in automobiles and public transport, all of which mean that we are expending fewer calories than our ancestors did.

This produces significant disease and disability in the population.


One of the three main sources of energy for the body. These are compounds made up of carbon, hydrogen, and oxygen and include sugars, starches, celluloses, and gums. There are several types based on size and shape: monosaccharides, disaccharides, trisaccharides, polysaccharides, and heterosaccharides. They are a key source of energy for the body. Each gram of carbohydrate has four calories.