Animated map of obesity incidence by state (1985-2006) (Photo credit: Wikipedia)

Here are some excerpts from the CDC about Obesity in the U.S.

Adult Obesity Facts

Obesity is common, serious and costly

More than one-third of U.S. adults (35.7%) are obese.
Obesity-related conditions include heart disease, stroke, type 2 diabetes and certain types of cancer, some of the leading causes of preventable death.
In 2008, medical costs associated with obesity were estimated at $147 billion; the medical costs for people who are obese were $1,429 higher than those of normal weight.

Non-Hispanic blacks have the highest age-adjusted rates of obesity (49.5%) compared with Mexican Americans (40.4%), all Hispanics (39.1%) and non-Hispanic whites (34.3%) [See JAMA. 2012;307(5):491-497. doi:10.1001/jama.2012.39].

Among non-Hispanic black and Mexican-American men, those with higher incomes are more likely to be obese than those with low income.
Higher income women are less likely to be obese than low-income women.
There is no significant relationship between obesity and education among men. Among women, however, there is a trend—those with college degrees are less likely to be obese compared with less educated women.
Between 1988–1994 and 2007–2008 the prevalence of obesity increased in adults at all income and education levels.