Roughly two-thirds of adults in the United States are overweight or obese, but there's a glimmer of hope on this grim horizon. After rising for nearly a quarter-century, the obesity rate for American adults ages 20 and older has leveled off at 34%, according to the latest report by the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics (NCHS).

That may be good news for some, but not all weight issues are created equal. Some groups still have a better chance of packing on the pounds than others. (The CDC considers adults overweight if their body mass index, or BMI, is between 25–29.9, and obese if it's above 30.) Here are some factors that influence weight.

Gender
Men and women have obvious biological differences, but they're not a factor when it comes to weight. Historically, women have been fatter than men, but that gap is narrowing. According to a November 2007 NCHS report, 33.3% of men and 35.3% of women were obese in 2005–2006.

“Men have been catching up to women,” says Cynthia Ogden, a CDC epidemiologist and the lead author of the study. “There arent significant differences anymore.”



Race
Race can be a bit of a wild card when factored into the gender equation. Men and women have similar rates of obesity, but the same can't be said for all races. For example, black women are more likely to be overweight or obese than their male counterparts.

Ogden says there are additional disparities between races and ethnicities. On average, non–Hispanic black women and Mexican-American women are heavier than non–Hispanic white women. For example, from 2005–2006, more than 50% of black women and Mexican-American women were obese, compared with only 39% of white women ages 40 to 59. However, in women ages 60 and older, the rate dropped dramatically for Mexican-American women and rose substantially in black women.

Mexican-American men have also been found to be heavier than both non–Hispanic black and white men.

Those differences are evident in children as well. A report published in the Journal of the American Medical Association examined data from 2003–2006 and revealed that 31% of white kids had a BMI at or above the 85th percentile—the CDC definition of overweight—compared with 35% of black children and 38% of Mexican kids ages 2 to 19.

“This is particularly true for girls," Ogden notes.

In general, obesity and overweight rates tend to be lower for Asian Americans and higher for American Indians.



Age
Rates also vary by age. Middle-aged men and women are more likely to be obese than young adults and the elderly.

The NCHS report found that the obesity rate for men and women ages 20–39 remains slightly under the national average at about 29%. Then, between ages 40–59, the rate spikes to nearly 41%. Later in life, however, the rates level off—dipping back under the national average when men hit 60 and women reach 65.

Of even greater concern is the prevalence of obese and overweight children: More than 30% of 2- to 19-year-olds in the United States qualify. A CDC National Center for Health Statistics study from the May 2008 Journal of the American Medical Association found that obesity rates have leveled off in school-age children, but more than 16% of kids are still obese—a number that has nearly tripled since 1980.

Whats worse, overweight kids are more likely to become obese adults. A December 2007 New England Journal of Medicine study reported that 80% of overweight children grow up to be obese adults.



Location
It also appears that geography can be destiny. In fact, the South has significantly higher rates of obesity than the rest of the country, according to the 2007 "F Is for Fat" report by Trust for Americans Health, a nonprofit, nonpartisan health advocacy group.

Of the 15 states with the highest obesity levels, 11 are in Trust for America's South region. Mississippi, West Virginia, and Alabama were the heaviest, weighing in with an average obesity rate close to 30%.

“The South is consistently the worse offender," says Jeffrey Levi, the executive director of Trust for Americas Health. But the rest of the country isnt too far behind. In 2007, every state, except Massachusetts and Colorado, had an adult obesity rate exceeding 20%.

The pattern rings true for children as well. The South has the highest prevalence of overweight and obese children, accounting for eight of the nine highest states. (The District of Columbia came in at number one.) According to the 2007 National Survey of Childrens Health, conducted by the CDC's National Center for Health Statistics, 16.5% of rural kids are obese, compared with 14.4% of urban children.



Socioeconomic status
Studies have shown that the lower the household income, the more likely the family members are to become overweight or obese. But researchers are finding that that relationship, which depends highly on race and gender, isnt so clear cut anymore.

“The perception is that the higher socioeconomic status, the less likely someone is to be obese,” says David Allison, a professor of biostatistics at the University of Alabama at Birmingham. “But when you drill down one layer deeper, you see things are more complicated than that.”

Socioeconomic status has a much greater affect on the weight of women than of men, according to a 2007 NCHS study published in Gastroenterology. For example, the chance that a white woman or girl will become obese increases as her household income decreases.

Surprisingly, the paper also showed that Mexican-American men of higher incomes were more likely to become obese.

However, there may be a more traditional correlation between socioeconomic status and obesity in children. According to the CDC, 22.4% of children ages 10 to 17 living below the poverty line are overweight or obese when compared with only 9.1% of children living in a household that generates four times that income.
Last updated: Dec 22, 2008