Epidemiology of Obesity - The Americas - United States

United States

The United States has the highest obesity rates in the developed world. This is a long-standing phenomenon: already by 1962, 45% of adult Americans were overweight, and 13% of adult Americans were obese; these numbers were already higher than obesity rates observed in most developed countries as late as 2001-02. From 1980 to 2002, obesity rates have doubled, reaching the current rate of 33% of the adult population.

As of 2007, 33% of men and 36% of women are obese. Rates of obesity vary between social groups, with minorities and low-income individuals more likely to be overweight. The rates are as high as 50% among African American women.

Geography is a major factor. The American South has been described alternatively as "Stroke belt", "Obesity belt", or "Diabetes belt", to reflect the fact that all residents of the region have high incidences of these three conditions, compared to people of the same race/ethnicity elsewhere in the country. The lowest obesity rates of major racial/ethnic groups across 50 states are thought to be among non-Hispanic white residents of Colorado and Hawaii, at around 16%. However, these numbers are based on self-reported height and weight data and likely to be underestimated (the bias is so large that, for example, estimates of obesity that rely on self-reported data arrive at the rate of 22% among non-Hispanic white females, whereas studies that involve direct measurement show that the rate is closer to 34%.)

The prevalence of class III obesity (BMI ≥40) has increased the most dramatically, from 1.3% in the late 1970s, to 2.9% in 1988-94, to 4.7% in 2000, to 5.7% in 2008. Among African American women, its prevalence is estimated to be as high as 14%.

The overall rate of obesity began to plateau in the '00s, but severe obesity and obesity in children continued to rise. In January 2010, a study published in the Journal of the American Medical Association found that the obesity rate for American women has remained constant over the last decade, with only small rises amongst men and children.

Obesity is one of the leading health issues in US society, resulting in about 300,000 deaths per year in the United States. About 65 percent of Americans are now considered either overweight or obese. According to National Health and Nutrition Examination Study collected between 1970s and 2004, overweight and obesity prevalence have increased steadily among all groups of Americans over the past three decades.